How do I fill out Form W-8BEN correctly?

Question

Freelance

Friends, such a question. A US customer we work with sent me a Form W-8BEN to fill out. I don't quite understand some points, please help me:
1) Mailing address (if different from above) - Do you need an email address here or just a regular mail address?
2) For some reason, this item is duplicated twice in this form: City or town, state or province. Include postal code where appropriate.
3) US taxpayer identification number (SSN or ITIN), if required (see instructions)
4) Reference number(s) (see instructions)
5) Special rates and conditions (if applicable—see instructions): The beneficial owner is claiming the provisions of Article ____________ of the treaty identified on line 9 above to claim a _______________ % rate of withholding on (specify type of income): _____________
Explain the reasons the beneficial owner meets the terms of the treaty article: __________________
6) Social Security Number:
Should be sent today, but I have no idea, especially points 3-6 are stupefied.

Answer 1

1) mail
2) don’t be stupid, duplicated in the case, look - answer
3) you don’t have it, you can’t get it (sSN) or it’s expensive for a long time (ITIN)
4) nothing, but see the instructions
5) special tax rate, nothing if competent boo, for the RF, it seems there are zeros all over
6) you don't have it n/a

Answer 2

Well, you ask him what to write there, he knows.