Hi,

By default as per my knowledge there seems no option to see who has validated the Inventory adjustment. You can get the id of the create user from the field create_uid and last updated users id from the field write_uid , still there we cannot ensure that the create_uid or write_uid is the user who validated the Inventory adjustment.

In the odoo core, it seems the inventory adjustment is not editable after validating the Inventory adjustment, so you can get the user from the field write_uid which give you the name of the Last Updated by .

You can add this field to the view either from the code or by editing the view from the front end in the developer mode.

Then in the view you can see,

You can change the field label accordingly.

If this is not acceptable override the Validate button function and store the validating users id to a new field.

Thanks