docs for B2 visa on port of entry

[gurgosal]

Hi,
which all documents are needed at the port of entry for US. I'll be travelling on B2 visa for 3 months to a friend. Will I need letter of invitation from the friend?

[sasvi]

Hi,
which all documents are needed at the port of entry for US. I'll be travelling on B2 visa for 3 months to a friend. Will I need letter of invitation from the friend?

Having the invitation letter, with the correct address, and the return ticket will make the interview smoother.

[gurgosal]

Having the invitation letter, with the correct address, and the return ticket will make the interview smoother.

Thanks. Does the invitation letter needs to be on official paper or having all the information on a simple paper would suffice?