Create the action from Object Manager, configure its layout, then add it to the page layout's Salesforce Mobile and Lightning Experience Actions section so users see it on the record.
- Open Object Manager and the source object
Setup > Object Manager > [object name] > Buttons, Links, and Actions. Click New Action.
- Configure the action
Set Action Type (Create a Record, Update a Record, Flow, etc.), Target Object (for create actions), Label (the button text), and Name (the API name). Save. Salesforce opens the Action Layout editor.
- Build the action layout
Drag the fields the user needs to fill into the layout. Keep it short. Add Predefined Field Values if any fields should be filled automatically from context.
- Add the action to the page layout
Return to the source object''s Page Layouts area. Edit the layout. In Salesforce Mobile and Lightning Experience Actions, drag the new action into the desired position.
- Save the layout and test as a user
Save the layout. Log in as a user assigned to the layout, navigate to a record, and click the action. Verify the layout shows correctly, predefined values populate, and save completes successfully.
- Actions only appear if they are on the page layout. Creating an action without adding it to the layout leaves it invisible to users. Test on the right record type, since action sections can differ per record type.
- The Highlights Panel shows three actions by default, the rest collapse into More. Put your highest-frequency action in position one or two; anything after that is essentially hidden.
- Predefined field values bypass validation rules during save in some edge cases. Test with the validation rules active so you do not ship an action that surprises users with errors only some of the time.
- Actions inherit user profile permissions for the target object. If the action does not appear or fails for some users, check Profile > Object Settings before debugging the action itself.