There are a few ways that you can edit your essay for free.
One way is to use a grammar checking tool like Grammarly. Grammarly will check your grammar and spelling for free and can be used online or by downloading the app.
Another way to edit your essay is to have someone else read it and give you feedback. This could be a friend, family member, or tutor. This person can help you catch any errors you may have missed and give you suggestions on how to improve your essay.
Finally, you can also use online resources like the Writing Center at Yourdictionary.com. The Writing Center has a free essay checker that you can use to check for grammar and spelling errors. They also have a team of experts who can give you feedback on your essay and help you improve it.