How do I find my iPad’s generation?

I have a refurbished iPad from a reputable company. No hard copy or soft copy documentation was presented with the sale. And so far, my limitation with Apple products is minimal. Under the link for iOS, I read 16.7.8. Which is nice to know but doesn’t help me order an appropriate protective cover. The cover received when I ordered my iPad, does not fit and he pencil ordered doesn’t work. I believe it may be a mismatch. Each item seems to have been sent from a different location. What can or should do? Emails have been ineffective.