How to write a formal letter

https://www.bbc.co.uk/bitesize/topics/zv7fqp3/articles/zkq8hbk

How to write an official letter

1. Set up your font and margins.
2. Create your heading.
3. Write your salutation.
4. Use your body paragraphs to state your reasons for writing.
5. Add your closing body paragraph and signature.
6. Mention and add your enclosures.
7. Proofread and send your letter.

https://www.papier.com/stationery/inspiration/how-to-write-a-letter-guide/