What greeting can I use at the beginning of writing an English email?

1, hope that you are well. I hope you are all right.

I hope you have a good holiday and find it easy to get back to work. I hope you have a good holiday and will come back to work soon.

Thank you very much for your email. I'm glad to hear that you and your family are well. Thank you very much for your email. I'm glad to hear that you and your family are well.

Thank you for your prompt reply. Thank you for your prompt reply.

I'm sorry I didn't reply as soon as possible, but I've been busy these weeks. I'm sorry I couldn't reply to you earlier, but I've been really busy in the past few weeks.

6. Thank you for contacting us about XXXX. (Less formal, more friendly) Thank you very much for contacting us about xxxx. (Not very formal, more friendly)

Thank you for contacting us to supervise XXXX. (more formal) Thank you very much for contacting us about xxxx (more formal).

Extended data:

1. If you don't know the recipient of the email, a business letter can start in any of the following ways:

Dear sir/madam, dear sir/madam.

If you don't know whether to write to Mr. or Ms., you can write:

Dear sir or madam, dear sir or madam.

If you know the other person's name, it's always good to write it in the email. If this is the first time you write to someone, you can start with any of the following ways: male: dear Mr. XXXX, female: dear Ms. XXX, female: dear Ms. XXX.