What does mandate mean

An official order or commission to do something. a commission by which a party is entrusted to perform a service, especially without payment and with indemnity against loss by that party

Used as a noun an official order or commission to do something.

the authority to carry out a policy or course of action, regarded as given by the electorate to a candidate or party that is victorious in an election

Used as a verb give (someone) authority to act in a certain way. assign (territory) under a mandate of the League of Nations