Question: Q: check mark

• If you cannot find the ✓, you should click the language and keyboard viewer in the top menu line:

select "show emoji and symbols" and find the "character" you want, e.g. in "bullets and stars".

• If you have the character and you want to put it in a pdf tekst with Preview:

open the doc in Preview, from the menu choose Tools->Annotate->Text: it creates two small blue dots with a square somewhere on the document, move that to the exact location where you want to use it, then enlarge if necessary and put the character(s) in. Then enter and save.