How To Write A Letter To A Penpal In Spanish . To whom it may concern, formal. How to address and format a letter in spanish. Hamomi Students Write Pen Pal Letters Hamomi Children's Centre from hamomi.org Make sure you tell your penpal what it is about their profile that stood out from all the others. Include details you would normally include when writing to a pen pal in this situation. Your name (or your pen pal's name) goes on the first line.