The skinny on sending Lin fanmail as of December 2016, according to his dad. To summarize:
The address is
4768 Broadway Unit 743
New York NY 10034
You will get a reply (somehow, eventually, I have no idea how he has time for this) even if you don’t include a SASE (self-addressed stamped envelope). Do include an appropriate SASE if you are sending pictures or programs for him to sign. Gifts that are meaningful to you are okay, just nothing expensive.
He was dictating answers to interns when he was in New York, closing with his signature. (His handwriting is… super messy. Plus, that’s a lot of volume, when he does sit down to do it.) (eta: He does still handwrite some of the replies himself.) Here are some examples of replies people have posted on twitter. I’m not sure if he’s sent any from London yet, I think maybe one batch?
My advice is to feel free to send what you really want to say and then be very patient.
hey y’all terrible people who thought that harry styles had sex with 4768 women in his free time when he was actually curled up under a blanket, reading high-quality adult literature you probably haven’t even heard of, how do you feel now