I do not know...i do not have noone..
Coach or diamond membership

If you are 2000+ Elo rated then you definitely need a coach not must have but it will be very beneficial for you to improve your play as things get complicated.
Under 2000 Elo you can work yourself up for free as long as you are willing to improve

Not enough info. If you're trying to improve, then at your level, you require neither.
What more information should I provide?

I don't know, but we don't know anything about you. If you just want to play for fun, for example, just get a cheap diamond membership or something.

Play for fun, understanding the game, learning what to study in order to do so, avoiding losing in the first 15 moves, things like that.

I would like to know which one should I get, what is your recommendation? thanks.
For your rating, go with the diamond membership. You can always ask question of others members to get advice.

There's a coach membership? I don't see it under membership or with a Google search.
In any case, I would suggest you soak up the information from a Gold or Diamond membership first. The only real advantage of a Diamond membership is the videos and you may find good equivalents on YouTube. I like the one's one chess.com because the lessons were designed to build on each other and I hear/see new material that builds on knowledge I already have.

There's a coach membership? I don't see it under membership or with a Google search.
In any case, I would suggest you soak up the information from a Gold or Diamond membership first. The only real advantage of a Diamond membership is the videos and you may find good equivalents on YouTube. I like the one's one chess.com because the lessons were designed to build on each other and I hear/see new material that builds on knowledge I already have.
Check in settings and you will see coach options, you can upgrade to GM coach too.
I would like to know which one should I get, what is your recommendation? thanks.