https://www.grammarly.com/blog/how-to-start-an-email/
The Six Worst Ways to Start an Email
1 [Misspelled Name],
Don’t misspell your recipient’s name. Ever.
Double-check the spelling of the person’s name and either get it right or omit it and use a generic greeting like Hi there. Although a nonspecific greeting may come off as impersonal, a misspelled name is a red flag that says you’re careless.
2 Dear Sir or Madam,
Have you ever read and responded to a letter that greeted you with Dear Sir or Madam? We’re going to go ahead and guess you haven’t. Not only is this salutation stiff and formal, it shows that you couldn’t be bothered to look up a contact name and address someone specific.
3 To Whom It May Concern,
The same sentiments that apply to Dear Sir or Madam apply here. If your letter opens with To Whom It May Concern, we’re probably going to assume it doesn’t concern us.
4 Hey! or Hey, [Name]!
Reserve this one for your friends and close colleagues. Otherwise, hey is glaringly informal and can even come across as disrespectful. Have you ever felt warmly greeted by someone saying, “Hey, you!”?
How my heart sings 