What are the rules on slow play and pace of play?

Under Rule 5.6 of the 2023 Rules of Golf:

• Unreasonable delay (Rule 5.6a): you must not unreasonably delay play, either during a hole or between holes. A short delay is allowed for reasons such as asking a referee or the Committee for help, injury or illness, or another good reason.
  • First breach: one penalty stroke.
  • Second breach: general penalty (two strokes in stroke play, loss of hole in match play).
  • Third breach: disqualification.
  • A delay between two holes is penalized on the next hole.
• Prompt pace (Rule 5.6b): a round is meant to be played at a prompt pace. It is recommended that you make your stroke within 40 seconds after you are, or should be, able to play without interference or distraction, and you should usually be able to play faster. Prepare for your next stroke in advance and be ready when it is your turn.
• Ready golf: in stroke play you may play out of turn in a safe and responsible way (Rule 6.4b(2)). In match play you may agree that one of you plays out of turn to save time.
• Committee policy: the Committee should adopt a Local Rule setting a Pace of Play Policy, which may set a maximum time to complete a round, a hole or a series of holes.