Rules

[Bellou7]

Hello is it possible to open several account?

[voriki]

It depends what the reason is. Technically you're not supposed to open multiple accounts, but I don't think there is a problem if, and only if, it has no negative influence to anyone at all.

For example, I have an alt account: https://boardgamearena.com/player?id=91115911
I named it voriki alt, clearly state it so in the profile description and have only played training games with it. No ELO influence, no other players involved. I just played myself in training games to try things out.
So I would say that that is allowed.

However joining in games with other players, especially when the main account and the alt account are at the same table, this would pose a huge problem. You could influence your ELO score, "cheat" through means of coöperation, etc...