Dear (random name),
How is living in South Korea for you? I hope you’re meeting new people and exploring new places over there. I’m writing this letter to tell you that I’m planning to attend a university for my bachelor degree in Biology. I plan to pursue a career in the medical field like I told you when we were little kids. Hopefully all goes well and I can become a doctor. Make sure to come visit me sometime!
Your dearest friend,
Your name