Finish email formal

https://english.stackexchange.com/questions/332/which-expressions-can-be-used-to-close-an-email

https://www.careercontessa.com/advice/how-to-end-an-email/
https://www.careercontessa.com/advice/how-to-end-an-email/

https://www.english-at-home.com/business/how-to-start-and-end-a-business-english-letter-or-email/

https://www.brafton.com/blog/email-marketing/how-to-end-an-email/