It sounds like you are trying to give your users the ability to deactivate a Customer Asset record from the Field Service Mobile app, but are having trouble accessing the necessary command buttons.
Firstly, make sure that the user has the appropriate permissions to edit and deactivate Customer Asset records in Dynamics 365. You can check this by going to the "Security Roles" section in Dynamics 365 and verifying that the user has the necessary privileges.
If the user has the necessary permissions, you may need to customize the Field Service Mobile app to display the required command buttons. One option is to use the Command Bar Customization feature in Dynamics 365 to add a custom button that allows the user to deactivate the Customer Asset record.
To do this, go to the "Command Bar" section in Dynamics 365 and select the form where you want to add the custom button (in this case, the Customer Asset form). Click on "Add Control" and select "Button" from the dropdown list. Give the button a name and select the appropriate icon.
Next, you will need to define the action that the button will perform when clicked. You can use JavaScript to create a custom function that deactivates the Customer Asset record. Once you have defined the action, save and publish the changes.
Now, when the user opens the Customer Asset record in the Field Service Mobile app, they should see the custom button that you created. Clicking on the button will execute the custom function and deactivate the record.
If you have already tried adding custom buttons and they are not showing up, you may need to further troubleshoot the customization process to ensure that the button is properly configured and published.