As far as grammar checking goes, I check it myself. I really feel that if you are a writer it's important to know your grammar and understand what it's for.
When I write I take my time. I stop when something bothers me and I stare at it and think deeply about what could be wrong — the answer comes in the form of either bad syntax, too much present perfect, or just too many short sentences that makes everything sound like a machine gun firing off.
There are grammar checkers online, one of them is “Hemingway”, which I think is fine as a double check.
Many of the grammar checkers are just following the school rules of grammar and will often tell you that the formulation of a sentence is wrong, when it isn’t. It’s just that the school ma’am in the machine says it’s wrong according to a basic programme that can’t understand your intonation.
I read that “Ginger” is another tool that you can use for free. It will help you to build more confidence in writing and after a while you should notice that grammar rules aren’t that hard to remember. Putting it into good practice is the head scratching part of it all — that’s what produces good writing. And good writing is what people love to read.
If you are absolutely in the dark about grammar, learn the difference between at least these four things and how to use them; present simple, past simple, present perfect continuous and simple.
Just knowing something about these four will give you tools to work with when you write. When you write in any form of grammar, think about how the reader might feel when they read the information presented in that particular style of grammar.Tools in your head are good, and they are much better than App like tools that we have to pay for.
I hope this helps you and thanks for the read and comment, all the best with your writing,