That sounds like a Form 1099-MISC, which is a tax form for the U.S. You’re sent those from an entity that pays you more than $600 USD within the tax year as a hired contractor, supplier, or freelancer, etc. In this case, you supply Envato with a product which they sell and then split the profit with you. What they paid you should be listed as “royalties” under number 2. That amount was reported to the US. government’s Internal Revenue Service to make them aware of the fact that you earned that much money and may now owe taxes on it.
For Americans, this is very straightforward and not at all complicated and I’m assuming you’re American and live in the U.S. since 1099’s are not required for foreign contractors. If you’re not an American, live outside of the U.S., and did get this form, this might be complicated for you. I suggest contacting Envato to find out what you need to do if that’s your case. You may also need to discuss this with the tax collection agency in your country to see if they give you credit for taxes you paid to the U.S. That amount is in box 4.
*WARNING - I’m not a tax expert