Laws of the Game
5. Video match officials
A video assistant referee (VAR) is a match official who may assist the referee to make a decision using replay footage only for a ‘clear and obvious error’ or ‘serious missed incident’ relating to a goal/no goal, penalty/no penalty, direct red card (not a second caution) or a case of mistaken identity when the referee cautions or sends off the wrong player of the offending team.
An assistant video assistant referee (AVAR) is a match official who helps the VAR primarily by:
watching the television footage while the VAR is busy with a ‘check’ or a ‘review’
keeping a record of VAR-related incidents and any communication or technology problems
assisting the VAR’s communication with the referee, especially communicating with the referee when the VAR is undertaking a ‘check’ / ‘review’, e.g. to tell the referee to ‘stop play’ or ‘delay the restart’ etc.
recording the time ‘lost’ when play is delayed for a ‘check’ or a ‘review’
communicating information about a VAR-related decision to relevant parties