In related actions ,after submitting the form ,the details are not updated in db

Set the 'submit: true' in your button widget. Should work!

it is already set to true

Can you please attach the interface code, and process screenshot for more info?

a!localVariables(
  local!pressedButton: "cancel",
  local!getdata: rule!test_getRequestByID(ri!id),
  {
    a!sectionLayout(
      contents: 
      {
        a!boxLayout(
          label: "Audit Approval Form",
          labelSize: "MEDIUM_PLUS",
          contents: {
            a!columnsLayout(
              columns: {
                a!columnLayout(
                  contents: {
                    a!textField(
                      label: "Comments",
                      labelPosition: "JUSTIFIED",
                      value: local!getdata[1].requestorComments,
                      saveInto: local!getdata[1].requestorComments,
                      refreshAfter: "UNFOCUS",
                      readOnly: true,
                      validations: {}
                    ),
                    a!dateField(
                      label: "Start Date",
                      labelPosition: "JUSTIFIED",
                      value: local!getdata[1].startDate,
                      saveInto: local!getdata[1].startDate,
                      readOnly: true,
                      validations: {}
                    ),
                    a!dateField(
                      label: "End Date",
                      labelPosition: "JUSTIFIED",
                      value: local!getdata[1].endDate,
                      saveInto: local!getdata[1].endDate,
                      readOnly: true,
                      validations: {}
                    ),
                    a!textField(
                      label: "Email Addresses",
                      labelPosition: "JUSTIFIED",
                      value: local!getdata[1].emailAddresses,
                      saveInto: local!getdata[1].emailAddresses,
                      refreshAfter: "UNFOCUS",
                      readOnly: true,
                      validations: {}
                    )
                  }
                ),
                a!columnLayout(
                  contents: {
                    a!textField(
                      label: "Requested By :",
                      labelPosition: "JUSTIFIED",
                      value: local!getdata[1].requestorName,
                      saveInto: local!getdata[1].requestorName,
                      refreshAfter: "UNFOCUS",
                      readOnly: true,
                      validations: {}
                    ),
                    a!textField(
                      label: "Requested Email :",
                      labelPosition: "JUSTIFIED",
                      value: local!getdata[1].requestorEmail,
                      saveInto: local!getdata[1].requestorEmail,
                      refreshAfter: "UNFOCUS",
                      readOnly: true,
                      validations: {}
                    ),
                    a!dateTimeField(
                      label: "Requested On",
                      labelPosition: "JUSTIFIED",
                      value: local!getdata[1].createdOn,
                      saveInto: local!getdata[1].createdOn,
                      readOnly: true,
                      validations: {}
                    )
                  }
                )
              }
            )
          },
          style: "#efefef",
          shape: "ROUNDED",
          padding: "STANDARD",
          marginBelow: "STANDARD",
          showShadow: false 
        ),
        a!columnsLayout(
          columns: {
            a!columnLayout(
              contents: {
                a!buttonArrayLayout(
                  buttons: {
                    a!buttonWidget(
                      label: "Cancel",
                      saveInto: {
                        a!save(ri!submit, false),
                        a!save(ri!test_requests, local!getdata[1])
                      },

                      submit: true,
                      style: "NORMAL"
                    )
                  },
                  align: "START"
                )
              },
              width: "AUTO"
            ),
            a!columnLayout(
              contents: {
                a!buttonArrayLayout(
                  buttons: {
                    a!buttonWidget(
                      label: "Approve",
                      saveInto: {
                       
                        a!save(local!getdata[1].auditEmail, loggedInUser()),
                        a!save(local!getdata[1].lastUpdatedOn, now()),
                        a!save( local!getdata[1].lastUpdatedBy, loggedInUser() ),
                        a!save(ri!test_requests, local!getdata[1]),
                       a!save(ri!submit, true)
                      },
                      submit: true,
                      style: "PRIMARY",
                      showWhen: ri!editable
                    ),
                    a!buttonWidget(
                      label: "REJECT",
                      value: "reject",
                      saveInto: {                 
                        a!save(local!pressedButton,"reject"),
                        a!save(local!getdata[1].requestStatus,cons!test_STATUS_TYPES[3]),
                        a!save(ri!submit, true)

                      },
                      submit: true,
                      style: "DESTRUCTIVE",
                      disabled: false,
                      showWhen: (ri!editable)
                    )
                  },
                  align: "END"
                )
              }
            )
          }
        )
      },
      showWhen: local!pressedButton= "cancel"
    ),
    a!sectionLayout(
      contents: {
        a!boxLayout(
          label: "Rejection Comments ",
          labelSize: "SMALL",
          contents: {
            a!columnsLayout(
              columns: {
                a!columnLayout(
                  contents: {
                    a!textField(
                      label: "Comment",
                      labelPosition: "JUSTIFIED",
                      placeholder: "Please Provide Rejection Comments",
                      value: ri!test_Requests.rejectionComments,
                      saveInto:ri!test_Requests.rejectionComments,
                      refreshAfter: "UNFOCUS",
                      validations: {}

                    )
                  }
                )
              }
            )
          },
          style: "#efefef",
          shape: "ROUNDED",
          padding: "STANDARD",
          marginBelow: "STANDARD"
        ),
        a!columnsLayout(
          columns: {
            a!columnLayout(
              contents: {
                a!buttonArrayLayout(
                  buttons: {
                    a!buttonWidget(
                      label: "Cancel",
                      value: "cancel",
                      saveInto: {
                        a!save(ri!cancel, false),
                        a!save(ri!test_requests, local!getdata[1]),
                        a!save(  local!pressedButton,"cancel")
                      },
                      submit: true,
                      style: "NORMAL"
                    ),
                    a!buttonWidget(
                      label: "Submit",     
                      saveInto: {
                        a!save(local!getdata[1].rejectionComments,ri!test_Requests.rejectionComments),
                        a!save(local!getdata[1].auditEmail, loggedInUser() ),
                        a!save(local!getdata[1].requestStatus,cons!test_STATUS_TYPES[3]),
                        a!save(local!getdata[1].lastUpdatedOn, now()),
                        a!save( local!getdata[1].lastUpdatedBy, loggedInUser() ),
                        a!save(local!getdata[1].completedOn,now()),
                        a!save(ri!test_requests, local!getdata[1]),
                        a!save(ri!cancel, true)

                      },
                      submit: true(),     
                      style: "DESTRUCTIVE"
                    )
                  },
                  align: "END"
                )
              }
            )

          }
        )
      },
      showWhen:local!pressedButton="reject"
    )
  }
)

please help me with  this code,  this interface  is used for submitting the form .In the interface it is working fine but in related action in record site ,nothing it getting updated 

Process screenshot also please

Everything looks fine to me. The only set of last questions I have is. 

1. How are you triggering this process? Have you mapped this process as a site page, as action or some other way. 
2. Are there any instances starting for this process?

How you are expecting your data to get updated in the DB when you haven't configured any WDSE node in process nor any smart service call in interface?