Нашёл 2 млн ответов for 'resign letter'.
https://www.wikihow.com/Write-a-Resignation-Letter
https://www.wikihow.com/Resign-Gracefully
https://www.wikihow.com/Sample/Letter-of-Resignation-Template
https://resumegenius.com/resignation-letters
https://resumegenius.com/resignation-letters/two-weeks-notice-samples
https://resumegenius.com/resignation-letters/life-situation-samples
https://eforms.com/resignation-letter/
https://eforms.com/resignation-letter/e-mail/
https://eforms.com/resignation-letter/immediate/
https://www.thebalancecareers.com/resignation-letter-samples-and-writing-tips-2063051