Documents in Promapp can be added by anyone with permission to create a process, but once added, they can only be edited by the appropriate document owners.
Document owners are set at the group level. All Promasters are default document owners, but additional owners can be added from the process group. Right-click on the group name in the process group list, and select [Edit Stakeholders]. At the bottom of the pop-up window you can choose to include the Process Group Champion, any Process Editors, or other users, either by name or role.
Process Groups
Process Editors
Roles and Responsibilities