About Presidential Pardons

In this thread https://www.straightdope.com/21344488/can-congress-override-a-presidential-pardon regarding the question of Presidential pardons, it is mentioned how Ford pardoned Nixon: Yet, how could Ford pardon Nixon who was not yet found guilty of anything? And, for that matter, how is it that a President simply resigns and walks away Scot-free from all charges brought against him?

A pardon may be given before conviction. Many people did indeed complain that Nixon “walk[ed] away Scot-free” while some of his subordinates went to prison, and it was probably a factor in Ford losing the election two years later.

Some previous threads that may be of interest: