I have primarily used Grammarly for proofreading my writing pieces. This is absolutely designed to fix the spelling errors, word choices, and the grammatical error in sentences. I do not have much experience in Turnitin. However, I have got the expression that it can be used to detect plagiarism. While checking their website, I come to know that they have the different resources to strengthen the writing skills. The source detection and the evaluation of the source we basically use in our writings can be used from Turnitin which will increase the integrity of the writing.