HOw to call related action in other UI where fv!identifier can't be able to pass?

Use a!recordActionItem() inside a!recordActionField() and pass the Id yourself via identifier.
fv!identifier only exists in a grid/record row context.

https://docs.appian.com/suite/help/26.6/Record_Action_Item_Component.html

Please explain in more detail what you try to do an what you experience.

In rules outside record type you pass the identifier using other variables that contain the primary key data in it. Like a local or rule input variable can have the data so you pass corresponding primary key field in the a!recordActionField(). You can refer the documentation of this component to understand it better.

In addition I suggest you to complete the Appian Developer Learning Path on Appian Academy to self-learn about basic Appian implementation with hands-on practices.

use a!recordfield() outside the grid, and in a!recordfield() use a!recordActionItem () in action parameter, in a!recordActionitem() give recordaction in action parameter

Hi ​@fayazm555959 ,

It is not necessary to pass exactly the fv!identifier to call the related action. Identifier basically refers to some primary ID. Use a!recordActionItem() and pass the ID (or record map for composite keys) directly in identifier

a!recordActionItem(
  action: recordType!Customer.actions.updateCustomer,
  identifier: ri!customerId 
)

Let me know if this helps.