Purchasing Two Personal Licenses Or One?

I am interested in buying VMP Pro.

I have a windows computer – that is what I do my development on. I have a linux server – that is what I host my website on.

Users download files from the server and I need to watermark each file.
I also need to test the files protected before I upload it to the server and let the users use it.

Do I need to purchase two licenses, one for my windows computer and one for my linux server? Or is one license sufficient? If I only need one, which one do I select when checking out?

If you are going to execute VMProtect on LInux - you have to purchase a Liunux license, otherwise Windows license will be enough.