To define the folder paths, you can go in "Options" > "Desktop environment" and click on the button "Path settings".

or in General: Only during the Installation of allplan (if you are takling about allplan) or the Workgroupmanager (if your allplan Licence contains it)
or maybe we do not understand your question ... (Allplan is not a single File CAD system !) see Training -> documentation -> Step by Step System Administration, Network Management (last updated for Version 2017, but still valid for 2019 .. )