Hello and happy Monday!
… и еще 7 непринужденных фраз, чтобы начать письмо.

Hе ограничиваетесь Hello и Hi, есть ещё Hey / Heya / Hi there / Hi everyone 🙌🏼

💚 Hope you're well.
💚 I hope all is well.
💚 Hope you're having a good Monday.
💛 I hope you're having a great week so far.
💛I hope you're doing well.
🧡Hope everything is going well.
🤍I hope things are going well for you.