Have you noticed that we are at the time of year to be inundated with offers from self-styled expert essayist in the English language, who seek the honour of writing yours and my dissertations, whether we want one written or not. Their written introductions to their abilities are usually linguistically weird and many are dire. Some invitations sent to write on your behalf, have at best the strangest syntax, but more usually, they are a jumble of meaningless vocabulary. If it wasn't sad, it would be most amusing. None of the offers to write for me, which purport to be in English, make the grade.
International students on foreign campuses often ask native-speaking friends to check over their work for grammatical errors and for general editing help. The work though, has been done by the student and not someone who is as far from the from the course work as is possible.
The offers to write dissertations (it is specific) are made to hook students, the very people who should have the capability to do their own research, compile it and present it. If you require a dissertation to be composed and written for you, (I do not include here, editing, or digitisation for presentation, nor people with specific disabilities ) there is no way, in my opinion that you should be in a higher learning environment.
If someone is negatively challenged, they may as well employ a ghost student on their behalf who will, at the right time, ghost write their qualifying papers for them. There is an easier option, but, far be it for me to recommend such a course of action. There are plenty of dubious sites in strange places that will make it even easier; they will, at a price, design a course, college and qualification on lovely parchment for you to flaunt far and wide, ad nauseum.