The Wyoming Democratic Party will postally mail a ballot to every registered Democratic voter in the state, asking for their choice for the Democratic presidential nomination. The ballot will use ranked choice voting. Anyone who holds the constitutional qualifications to be president, and who states intention to seek the Democratic nomination, and who pays a fee of $2,500, may appear on the ballot. See the rules here.
The ballots must be postmarked no later than March 20, and must arrive at the party office by March 28.
Wyoming is one of the few states that has never had a government-administered presidential primary.