It's always best to make copies of everything that you send. With the function repport it's best to write as much detail as you can. Use attachments when there is insufficient space on the form. It's always better if you get your medical evidence and submit it to the SSA. The claims examiners are way too busy to follow up with doctors that don't respond.
Get you doctor to fill out an RFC form (Residual Functional Capacity) that describes the limitations that prevent you from working. **
Good luck