In German, there are many different salutations and closings for letters and emails. Which one you choose will depend on your relationship with the person you are writing and whether they identify as male or female.
Friends who write each other emails may simply write Hallo Gitta, or Hallo Micha, or Hallo zusammen, (if addressing a group). For this salutation, the comma comes after the name and not after Hallo as it would in longer sentences.
However, unless you are on very casual terms with someone, you will need to use the other salutations and make sure you use the appropriate declension. If you have never met a person and know that the circumstances are formal, you will want to use Sehr geehrter or Sehr geehrte which literally translates as "Very honored..." If you don't know exactly who will receive your letter, Sehr geehrte Damen und Herren, is the German version of "Dear sir or madam."
Gut. Also... „Sehr geehrte Frau Larsen, vielen Dank für Ihre Rückmeldung“.
Good. So... "Dear Ms. Larsen, Many thanks for your response."
Captions 17-18, Das Lügenbüro - Die Bewerbung - Part 1Play Caption
„Sehr geehrter Herr Frederick“, sagte er, „lassen Sie das sofort nach, sonst hau ich Ihnen eins auf die empfindliche Nase“.
"Very honorable Mister Frederick," he said, "stop that immediately, otherwise, I'll sock you one on [your] sensitive nose."
Captions 32-33, Piggeldy und Frederick - Der BriefPlay Caption
Lieber or Liebe which translates simply as "Dear" is more flexible. It may be followed by a first name (Lieber Hans,) or a formal term of address (Liebe Frau Hoffmann,), and is used for different types of friends and acquaintances.
„Lieber Tiger, teile dir mit, dass es mir gut geht“.
"Dear Tiger, I'll share with you that I'm doing well."
Caption 17, Janoschs Traumstunde - Post für den TigerPlay Caption
One important thing to remember is that the first word after the comma is usually not capitalized like it would be in English.
When concluding your letter or email, there are a number of options. The typical closing for formal letters is Mit freundlichen Grüßen, which the Schlager star Heino recently used as an album title when he covered other musicians' songs.
Er covert auf seinem Album „Mit freundlichen Grüßen“ Rock- und Popsongs.
He is covering rock and pop songs on his album "With Friendly Greetings."
Captions 5-6, Heino - Neue VolksliederPlay Caption
Other closings for formal acquaintances include Herzliche Grüße, ("Heartfelt greetings") and Viele Grüße, ("Many greetings"). Between friends or informal acquaintances, Liebe Grüße, or simply Lieben Gruß, or Grüße, are more common options.
„Liebe Grüße, Elisabeth“. -Elisabeth?
"Kind Regards, Elisabeth." -Elisabeth?
Caption 46, Die Pfefferkörner - Gerüchteküche - Part 3Play Caption
For more vocabulary related to letter-writing, go to Yabla German and watch the full episode of Piggeldy and Frederick in which the brothers tackle the topic. More salutations and closings can be seen on this informative website. For a more detailed account of how to use punctuation with the word Hallo, you can look at this Duden article.