an app to help with writing?

iOS and iPadOS

I need an app to help me with editing my writing. Like a grammar checker I guess. I found a spellchecker that works wonderfully, but it doesn't help with grammar mistakes. I want to nap we're all like have to do is copy and paste my text and it would check it for me. Is there an app or a wordprocessing app that does this? Thanks in advance. And if anyone is interested, I can give the link to the spellchecker app I have found.