Action layouts and predefined field values
Key Takeaway
A predefined value lets an action fill in a field automatically, so you can take that field off the action layout. If you remove a required field without giving it a predefined value, users can't save the record.
Every quick action has an action layout: the short form of fields a user fills in to complete the action, such as creating or updating a record. A predefined field value (or predefined value) lets the action fill in a field automatically. Data stays consistent, and you can take fields off the form so the action is faster to use.
How action layouts work
An action layout controls which fields users must fill in to complete a quick action. Both object-specific actions and global actions have one.
When you save a new action, Salesforce fills its action layout with a default set of fields. Salesforce automatically adds every required field from the target object and marks each one with a red asterisk. You can then add, remove, or reorder fields so users see only what they need.
You edit an action layout in the action layout editor, which is like the page layout editor but for actions. The palette at the top holds fields from the action's target object, and the action layout sits below it.