Twenty20 Match format and rules

Format
Twenty20 match format is similar to limited overs cricket in that it involves two teams, each have a single innings, the key difference being each team bats for a maximum of 20 overs. In terms of visual format, the batting team members do not arrive from and depart to traditional dressing rooms, but come and go from a "bench" (typically a row of chairs) visible in the playing arena, analogous to Association Football's "Technical area" or a baseball "dugout".

General rules
The Laws of cricket apply to Twenty20, with some exceptions:
Each bowler may bowl a maximum of only one-fifth of the total overs per innings (generally four, for a full, uninterrupted game). i.e., 4 in the 20 overs
Should a bowler deliver a no ball by overstepping the popping crease, it costs 1 run and his next delivery is designated a "free-hit", from which the batsman can only be dismissed through a run out, as is the case for the original "no ball". (Strictly speaking, the very rare methods of dismissal from a "no ball" – for hitting the ball twice, obstructing the field or handling the ball – also apply to the "free-hit" delivery.)
Umpires may award five-run penalty runs at their discretion if they believe either team is wasting time.
The following fielding restrictions apply:
No more than five fielders can be on the leg side at any time.
During the first six overs, a maximum of two fielders can be outside the 30-yard circle.
After the first six overs, a maximum of five fielders can be outside the fielding circle.
If the fielding team doesn't start to bowl their 20th over within 75 minutes, the batting side is credited an extra six runs for every whole over bowled after the 75 minute mark; the umpire may add more time to this if they believe the batting team is wasting time.

Tie deciders
If the match ends with the scores tied and there must be a winner, the tie is broken with a one over per side "Eliminator" or "Super Over"
Each team nominates three batsmen and one bowler to play a one-over per side "mini-match", referred to as a "One1". In turn, each side bats one over bowled by the one nominated opposition bowler, with their innings over if they lose two wickets before the over is completed. The side with the higher score from their over wins:

If the teams finish tied on runs scored in that one over, the side with the higher number of sixes in its full innings and in the one-over eliminator will be declared the winner. If the teams are still tied, the one with the higher number of fours in both innings will win.
Tied Twenty20 matches were previously decided by a "Bowl-out".