According to USA tax policies we need to make sure you comply with either of the following:

1. In case you pay taxes in the USA (USA citizen, etc.), you need to send us a copy of your W9 form.
2. In case you do not pay taxes in the US (most of you), we need you to fill out W-8BEN form.

Steps:

1. Download/print form from here: https://www.irs.gov/pub/irs-pdf/fw8ben.pdf
2. Fill in the form and sign it.
3. Upload the signed document.