cannot place text above music score

Sorry to hear to you are having problems! First, though, to be clear: you might have paid $60 for an account on the separate score-sharing website musescore.com, but that has absolutely no bearing whatsoever on the MuseScore notation software on your compute.r That is always completely 100% free, no way to pay anyone anything for it even if you wanted to.

Next, regarding the text: you don't say which tutorial you watched, or what you did to try to enter text, but as described in the free online Handbook you can access from the Help menu within MuseScore, simply click a note and then Ctrl+T (Cmd+T on macOS) and you can type text.

if the goal is to have note names over every note, though, no need to resort to doing this manually. There is a plugin to do it automatically, or even better, simply right-click the staff, Staff/Part Properties, then Advanced Style Properties, and now you can select from various options to place note names directly within the notes, and they even update automatically if you then add or change notes.

if you continue to have trouble, please attach your score and tell us more precisely what you are trying to do, what you are clicking or pressing to make it happen, and what happens instead.