Go to users and tick "Mass Activities Dynamic Action".

The "Mass Activities Dynamic Action" list view.

In the "Mass Activities Dynamic Action" form view, define the action name and select applies to & group for that action and click "Add Action" to add that action in the selected model.

Note: This is only useful to main models not for an internal model like(sale order line, purchase order line), etc. as in odoo standard separate views are not there for that kind of models, if you have a separate view for that kind of model than you can use it we don't have any restrictions for that.

Click "Remove Action" to remove that action from the selected model.

Select records from the list view in which you want to apply that action, and after that go to "Action" and apply that action, It displays action in that group only which was configured.

Action is not displayed in that group which was not assigned in the configuration.

Select records from the list view in which you want to apply that action, and after that go to "Action" and apply that action.

Enter details and press "Schedule".

Action applied in all the selected records.

Action applied in all the selected records.