When a button visible on any record is clicked, the text on it (Approved, Paid etc.) will be written on that particular record like a stamp. An action like sending a message, an email or a Form (assignment) can be triggered, too.
You can create buttons as much as you want (Settings / Button Settings); define the text and choose the Roles of users who will be authorized to see or click for each one.
Click Forms menu and "Edit Form" button of a Form in order to select Buttons which will be visible on that Form.