on Just Publishing Advice:
ProWritingAid is up there with the best if you need an online writing assistant
For more and more writers, an online grammar checker is becoming a must-have editing tool.
Any tool that highlights common grammar and spelling mistakes and offers quick and easy corrections is going to help improve your writing.
There are a lot of free writing tools available online now, and most of them can offer you some basic help.
But to get really useful, in-depth analysis of your grammar and style, you will need to consider using a premium version editing tool.