"Pen pal in English" is how you say "pen friend" in English.
A pen pal is a person with whom you write letters (usually) to, even though they live far away. The practice of having a pen pal began in the 1800s, and it was quite common for young people to exchange letters with someone they had never met. Today, while this practice has decreased, many people still enjoy having a pen pal as a way to make a new friend or to improve their writing skills.
