Depends on the kind of match.
A National Match rifle is usually made for NRA Service Rifle competition. The rifle must have an external appearance of a general issued rifle. An AR would have a 20" barrel use standard hand guards and use iron sights. To get competitive the rifle may be fitted with a stainless steel match barrel, the hand guards may be free floating and he sights may be finer in size and adjustment. Triggers cannot be less than 3.5 lbs if I remember right or it may be 4.5 lbs.
My match rifle has a cryogenic treated stainless match barrel, floated barrel, 1/4 moa adjustable sights, a RRA match trigger and the upper andover have been bedded at the take down and pivot pin lugs. Mine has no bayonet lug or ash hider as these are optional. Slings can be leather or canvas of an issues style and I chose canvas as it is easier to get set up for timed stages.
A match will usually start with 200 yd offhand slow fire shooting with no sling.
Then 200 yd timed fire from sitting.
300 yd timed fire from sitting or kneeling.
300 yd rapid fire from prone.
600 yd timed and slow fire from prone.