Does Affiliatly manage tax documents like W9 or 1099?

We do not provide any tax forms nor track such information. You would need to request that from your affiliates separately.

To fill your Form 1099-MISC you'll need to collect the W9 forms from all your affiliates that had more than $600 in sales during the calendar year. This way you'll get their tax information as it's part of the details your 1099 requires.