TLDR: If you want to know, your best course of action is to email and ask.
Long answer: Both sites are technically, at the moment, open to "international" registration. According to Spanish regulation, there is nothing permitting them from allowing players in any country whatsoever. In reality, they will only allow players from countries where it is broadly deemed legal to allow online poker licensed offshore. This generally precludes countries with local regulation, like the UK, Denmark, and Belgium, and clear black-market countries like Australia and the United States.
But what that means for each site will differ. Colombia is one of those countries where it is somwhere on the black-white spectrum. Probably leaning more towards black from offshore - they have a local licensing regime, but no international operators have a license. PokerStars have stated that they have withdrawn from the market, and I would guess that applies to PokerStars.ES. They are currently using their withdrawal as somethign of a bargaining chip to try and get better regulations for online poker (specifically, international player pools). Winamax might be flouting the local laws and allowing play.
You probably aren't going to get an official list of countries permitted at each site. Your best bet is to email customer support and ask.
1) Do spanish online players need to deduct TAX off their cashout amounts to spanish gov?
2) Do EU players who play on ES, need to TAX aswell to spanish gov or only to own gov?