First of all, by default this option is disabled (we like to keep things simple). So if you want to enable the users to move items to other files, the SuperAdmin will have to first set:
these permissions to "Everyone" (or limit it to Managers and other SuperAdmins). Don't forget to click "Save Changes" at the bottom of the page.
Once this is set, users can move items in their files. To do so, find the snap/form you would like to move and click the "edit" icon (pencil) to get the edit window:
Then click "Advanced" and find the "move to another file" box, where you can type the reference of the file you would like to move the snap/form to.