There are a huge array of creative uses for the Prestidigitation cantrip that can leave DMs scratching their head over a ruling. Let's start with the exact wording, as written in the Player's Handbook (PHB):
"This spell is a minor magical trick that novice spellcasters use for practice. You create one of the following magical effects within range:
You create an instantaneous harmless sensory effect such as a shower of sparks a puff of wind faint musical notes or an odd odour.
You instantaneously light or snuff out a candle a torch or a small campfire.
You instantaneously clean or soil an object no larger than 1 cubic foot.
You chill, warm, or flavour up to 1 cubic foot of nonliving material for 1 hour.
You make a colour a small mark or a symbol appear on an object or a surface for 1 hour.
You create a nonmagical trinket or an illusory image that can fit in your hand and that lasts until the end of your next turn.
If you cast this spell multiple times you can have up to three of its non-instantaneous effects active at a time and you can dismiss such an effect as an action."
On top of this description, it's useful to keep in mind that Prestidigitation has a casting time of 1 action, a range of 10 feet with verbal and somatic components.