I imagine that you could choose either of two options
- install dataview, and then paste Angel’s codes, switch to Read Mode, and you should have what you want.
- install templater, visit the templater documentation page, and find out how to do what you want using the examples on the documentation page.
The advantage of the templater option would be that the code would paste the actual date. Whereas the Dataview option can render the date from the note’s metadata but only whilst in read mode.
Good luck!