Hello, I wanted to know if I can use the Post Office address as my physical address since I have a PO Box on site? If I could how can will I enter my box number under unit/apt section? Cause some places don't accept PO Box as my physical address.

You will have to go to the post office and sign up for it...you can only use the address when receiving packages from ups and fed ex because they can not deliver to post office boxes. Once you get the paperwork in...you'll use the address and add your box number in the apt/ste #section.

I use my P. O. box as my address, but the Post Office wants a street address. That doesn't protect you if someone wants a street address.