Want to add Dynamic Mobile number

Initialize the local variable

a!localVariables(
  local!add,
  local!npi: 0,
  a!sideBySideLayout(
    items: {
      a!forEach(
        items: local!npi,
        expression: a!sideBySideItem(
          item: a!textField(
            label: "Mobile Number",
            labelPosition: "ABOVE",
            value: fv!item,
            saveInto: fv!item,
            validations: if(
              a!isNullOrEmpty(fv!item),
              {},
              if(
                not(
                  regexmatch("^([0-9]{" & 10 & "})$", fv!item)
                ),
                "Maximum " & 10 & " digits are allowed",
                ""
              )
            )
          )
        )
      ),
      a!sideBySideItem(
        item: a!linkField(
          label: "",
          links: {
            a!dynamicLink(
              label: "Add New",
              value: { local!npi + 1 },
              saveInto: {
                a!save(local!npi, append(local!npi, save!value))
              }
            )
          }
        )
      )
    },
    
  )
)

below code doesnt add new field i dnt know whats the issue.can u check pls

a!columnLayout(
  contents: a!localVariables(
    local!phone: if(a!isNullOrEmpty(ri!editGrid.lead.phone)," ",ri!editGrid.lead.phone),

    a!columnsLayout(
      columns: a!columnLayout(
        contents: {
          a!richTextDisplayField(
            labelPosition: "COLLAPSED",
            value: {
              a!richTextItem(
                text: "Phone",
                style: "STRONG"
              )
            }
          ),
          a!forEach(
            items: local!phone,
            expression: {
              a!sideBySideLayout(
                items: {
                  a!sideBySideItem(
                    width:"10X",
                    item: a!textField(
                      label: cons!PRO_TXT_LABEL_PHONE & " " & fv!index,
                      labelPosition: "COLLAPSED",
                      placeholder: "-Enter Phone Number-",
                      value: fv!item,
                      saveInto: {fv!item,
                      a!save(local!phone,fv!item)},


                      refreshAfter: "UNFOCUS",
                      validations: {},

                    )
                  ),
                  a!sideBySideItem(
                    item: a!richTextDisplayField(
                      labelPosition: "COLLAPSED",
                      value: {
                        a!richTextIcon(
                          icon: "times",
                          altText: "Remove number",
                          link: a!dynamicLink(
                            saveInto: a!save(
                              local!phone, remove(local!phone, fv!index)
                            )
                          ),
                          linkStyle: "STANDALONE"
                        )
                      },
                      showWhen: count(local!phone) > 1
                    ),
                    width: "AUTO"
                  )
                },
                alignVertical: "MIDDLE"
              )
            }
          ),
          a!richTextDisplayField(
            labelPosition: "COLLAPSED",
            value: a!richTextItem(
              text: {
                a!richTextIcon(
                  icon: "plus",
                  altText: "plus"
                ),
                " ",
                "Add phone number"
              },
              link: a!dynamicLink(
                saveInto: {
                  a!save(local!phone, append(local!phone, ""))
                }
              ),
              linkStyle: "STANDALONE"
            ),
            accessibilityText: "Clicking this link will add another phone number input above."
          )
        },
        width: "NARROW_PLUS"
      )
    )
  )
)

Following page has the details on what you are looking for - 

https://docs.appian.com/suite/help/22.4/recipe-add-multiple-text-components-dynamically.html

looks like it is a duplicate post https://community.appian.com/discussions/f/general/27997/dynamically-add-mobile-number