There's several places where you could do this and hire these people where there's an actual escrow built-in and there's a protected by her for both you and employee.
For example, fiverr and similar websites come to mind. The prices there seem to be very reasonable, but I have not used their service before. Also writing can be very specific. Someone who writes comedy might be terrible at writing an article about crypto for example. I have seen articles in major financial publications like WSJ and Forbes, written by professional financial writers, that have outright false information about bitcoin (such as "Bitcoin is 100% anonymous"). Do you have any examples, maybe an article in the style that you are looking for? Just a suggestion.