How cam you write letters to Zac Efron so that he can reply to them?
You can write letters, but there's a 99% chance that he wont reply to them (or even read them). Like leahfox said, you can buy a disney channel magazine or whatever and near the end there's a list of a bunch of disney stars with their mailing address (remember, this IS NOT their actual address! xD) and you can send all the fanmail you want. =D
buy a disney channel magazine.