I cooked with some ground beef 3 days ago but didn’t use it all and wrapped it in saran wrap and put it back in the fridge. Can i still use it?

Can you clarify? I read this as you did not use all the RAW ground beef and that is what is in the fridge. I would not chance using if it has been in there for 3 days. Sorry...

I copied and pasted this from the USDA food safety website:
Can I refrigerate or freeze leftover cooked hamburgers? How should they be reheated?
If ground beef is refrigerated promptly after cooking (within 2 hours; 1 hour if the temperature is above 90 °F), it can be safely refrigerated for about 3 or 4 days. If frozen, it should keep its quality for about 4 months.
When reheating fully cooked patties or casseroles containing ground beef, be sure the internal temperature reaches 165 °F (73.9 °C).

Cooked beef is good for 3 to 4 days in the fridge. Best use on fourth day/immediately.