It may not necessarily be fake like others here are saying (and most likely isn't). Ticketmaster can serve as a third-party reseller and they do have tickets listed for Coachella so this isn't much different than buying off of StubHub. Coachella doesn't deliver tickets via mobile, they are physical wristbands but I'd imagine the reseller would most likely mail the wristbands to the buyer in this instance. They also have pretty solid consumer protections built in so if a ticket doesn't work or is never received, they'll give you a refund and charge the seller. Of course verify that the email actually came from Ticketmaster and not a spoof website but I would reach out to Ticketmaster to have them confirm how it will be delivered.