What is Twenty20 or T20 in cricket?
Twenty20 or T20 for short is a shortened version of the game of cricket in which each side faces a maximum of 20 overs. The game typically lasts about 4 hours with a quick turn between innings unlike other forms of the game, thus increasing its viewership and popularity. 

This format was introduced by the England Cricket Board in an inter-county competition back in 2003. Since then, its become really popular with several international competitions and country wide leagues across all the major cricket playing nations world wide
O que é um Twenty20 ou T20 no críquete?
O Twenty20 ou T20 para abreviar é uma versão abreviada do jogo de críquete em que cada lado enfrenta um máximo de 20 overs. O jogo normalmente dura cerca de 4 horas com uma curva rápida entre as innings, ao contrário de outras formas de jogo, aumentando assim sua audiência e popularidade.