hello, this might be better. After a long vacation, it's time to start learning. The Japanese Language Club is resuming its work this week. Join us to remember the studied material, and we also invite those who are keen on Japanese culture and are ready to plunge into the world of Japanese hieroglyphics. Have a nice day.

In terms of functionality, it's fine. Depends how 'nitpicky' you want to be, though. There shouldn't be spaces before commas (i.e. 'studied material, and also' etc.), and there's a case for expressing it as 'and we also', owing to how that's more natural to say, even though grammatically, both are fine. And 'Japanese hieroglyphics' may confuse people about the various Japanese scripts, unless you're referring to something else, so you may want to confirm what you're referring to as it may be better to say 'Japanese hieroglyphs' instead, though, I concede, this is only a point of pedantry.

After a long vacation, it's time to start learning (again). The Japanese Language Club is resuming its work this week. To remember/revise the studied material , and also we invite those who are keen on Japanese culture and are ready to plunge into the world of Japanese hieroglyphics. Very well written. You can add an optional again at the end of the first sentence. Also the word come is not correctly used or clear for the start of the second sentence. we also= is the natural way for your context, but the word also is often added before or after, what is being compared or spoken about. It is a matter of personal preference. Many times it does not change the meaning. "The Japanese Language Club is resuming its work this week. To remember the studied material , and also to offer classes in Japanese writing skills". <-- also can go first or second for this sentence "The Japanese Language Club is resuming its work this week. To remember the studied material , and to also offer classes in Japanese writing skills". <-- also can go first or second for this sentence but for "we" we say "we also" <-- also at the end.

The only error I can see is there should not be a space in front of the comma. So "material , and" should be "material, and".

Nice.