Using an online grammar checker such as grammarly is an essential. While you are writing, you get carried away in your ideas that you don’t often use perfect grammar or spelling. That’s why a grammar checker like grammarly.com, grammerlookup.com, or prowritingaid.com can be a really great tool.
You can use any of the services above for free to a certain extent, or you can get the pro version. I have used the free feature on all of them and it has worked pretty well.
The Grammarly.com version can be used either by copy-pasting your writing into their online page or you can install a browser extension. The free version checks for spelling errors, missing words, basic incorrect punctuation, clarity, engagement, and then gives you an overall score out of 100.
When you get the pro version, it checks for more advanced writing issues like intricate text, word choice, punctuation in compound or complex sentences and more.
Prowritingaid.com does bascially the same thing as grammarly, but it checks for a little bit more than the other.
It looks for spelling issues, grammar issues, style issues, overused words on the first 500 words (more if you get pro), repeats on the first 500 words (more if you get pro) and other such things.