If I understand it correctly, yes you can register for a user and post in behalf of them. You can provide them the access login information later on so they can post on their own.
Just let me know if you are asking and referring to a different thing.
Please help our moderating team work more efficiently by not sending us support questions via PM. You can read more about how AppThemes support works
here. However, you can send a PM to follow up and remind me if I missed your support request/thread.
Thank you and have a nice day.
