You can save the user password with the path document so the client can connect directly to the server. A path document allows you to access a specific 4D Server database directly from the client machine either by dragging and dropping this file into a 4D Client application or by double-clicking on it provided it is properly set to be opened with 4D Client. To create this document, check this tech tip: https://kb.4d.com/assetid=34478
To save the password when you create this document, you need to have the option "Users can change their password" checked in the Application->Access setting of the database preferences.
By doing this, the save password option will be available when you create the path document.