It’s tempting to just tell you that that’s a pretty name (and it is pretty, especially if you understand Greek), but honestly, I’ve never heard it used in English in my life. Worse than that, I suspect most English speakers would have no idea of how to pronounce it, or if they heard the name, they would have no idea of how to spell it. One problem is the “ch”, which should be pronounced /k/ in English (as in “charisma”), but which English speakers would be tempted to pronounce as the “ch” in “cheese”. The second problem is the “a”, which I would pronounce /a/ as in the original Greek, but the pronunciation /ei/ is probably considered more standard in English. Sorry to be a downer, but this is an important decision, and you should have full information. Honestly, you could just as easily use a Burmese or Chinese name — it would not be any more exotic to most English speakers. In fact, English speakers are used to speakers of other languages using their real names, rather than an English name. I hope my brief comments are helpful to you.

It's a very nice name, but it's not English - - At least I've never heard in in the last 5 or so decades.

Very pretty name but as a native English speaker from the US, it's new to me. Congratulations on the birth of your new baby.

You could also spell it - ‘Carys’. This is a bit more common than Charis I think. I don’t know anyone by that name, but I have a couple of friends with the name Carys. I think it is pronounced the same. But it’s good to be unusual, so Charis would be a lovely rare name.

I see it is a real name and a good word: https://en.m.wikipedia.org/wiki/Charis_(name) The pronunciation might be an issue, but if your child can cope with that it's fine. Congratulations.