In Germany, the first letter a child gets is one that gets sent automatically, assigning them a tax number. A letter from the President is much nicer. However, German parents can apply for the President to be the honorary godfather of their seventh child.
The funniest thing with this tax letter is that on the envelope it says “Karriere mit Zukunft” meaning “careers with a future” like they completely seriously expect your newborn baby to start working for them 18+ years down the line.
I sent Bill Clinton an invitation to my high school graduation party, and got a letter back from the White House telling me to work hard in college.
But mailing a birth announcement to the White House is a much better idea. They send a card back to the child welcoming them to the world. You can file it away and then give it to your kid when they are an adult and tell them this is the first letter they ever got.