Is it Legal to Hire a ghostwriter to Write a Thesis?

I am a postgraduate student and I need help in writing my thesis. My idea for the thesis has been approved and I have already started the research, but my writing skills are very weak, which is why I was hoping if I can hire a professional ghostwriting agency to get the services. The only issue is that I am not sure whether hiring a ghostwriter or ghostwriting agency is legal or not. Will it is safe if I will hire someone to write the thesis, and I will provide all the relevant material and research work to them? Can someone kindly provide some guidance?