It depends is a common answer I give to my students often in response to many questions. The old school answer is yes you should take a divot with irons just like a dollar bill shape. But it depends on many factors if you should take a divot with irons.
1) what turf do you play on? If zoysia like my club Old Hickory the ball sits up so high that a divot may not be required. If tight bent or bermuda probably yes.
2) what club is it? SW or PW probably so as they have more shaft lean as compared to say a 4i which is probably little or no divot.
3) what is your Trackman Angle of Attack? I have seen players with a -7 AoA who take no divot and players with +1 or higher take huge chunks.
So the answer is it depends! If your angle of attack is negative with irons and your club path is between -3 and +3 if you take a divot Great! If you don’t Great! If your angle of attack is too shallow and positive and your path is outside those parameters then find an instructor that can help!