-Link vídeo_ writing a formal letter: https://www.youtube.com/watch?v=G0EXT89D4Jk

- How to Write a Formal Business Email in English: https://www.youtube.com/watch?v=CFjzS_KUFQs

- Formal and Informal Business Request Emails in English: https://www.youtube.com/watch?v=ZV4RYhHLb7g

-How to Write Informal Business Emails in English:https://www.youtube.com/watch?v=W_9PNT_81vs