I’ve moved your posts into the same topic, as they’re asking much the same question.
You can add as many keywords to the meta keywords tag as you like and Google won’t care, because Google has not used that tag in its algorithm for a good number of years. I don’t know if any of the other search engines pay much attention to it. My advice would be to save yourself time and effort and not bother adding it at all. If you feel you must use it, then remember that there is absolutely no point in adding keywords here if they don’t appear in the text on your page.
As far as using keywords generally goes, you should use as many as you need to make your text intelligible and interesting for your readers. Forget about keyword stuffing.
You might find some helpful information about keywords in these articles:
If you’re new to SEO, I’d highly recommend that you read Google’s “Search Engine Optimization Starter Guide”. Follow the advice in that, and you won’t go far wrong.
In future, please remember to search the forums before posting, as you’ll often find your question has already been asked and answered. For example: