There are several common greetings and “endings” in German, just as there are in English. Here are the standards:

Hallo! – Hello

Guten Morgen – Good morning. We often shorten this to “Morgen”.

Guten Tag – This translates literally to “Good day”. We use this throughout the day and it is a good option when you might want to say “Good afternoon” in English, a translation for which does not exist in German. The direct translation of “Good afternoon” would be “Guten Nachmittag” which is nonsense in German. We often shorten “Guten Tag” to simply “Tag”.

Guten Abend – Good evening. We often shorten this to “Abend” but according to some native German speakers, it should actually be shortened to “n Abend”, taking the “n” from “guten”.

At the end of the day, we say:
Gute Nacht for good night.

At the end of a conversation, either in person or over the telephone, we often say:
Tschüss which means good-bye or bye and is generally considered informal.

Ciao – While this may be Italian, it is often heard as an informal good-bye amongst friends in Germany.

In person we might say:
Auf Wiedersehen! Or simply “Wiedersehen!”. This means “See you soon!” or “So long”.

Other informal expressions to say goodbye include:

Bis dann! This literally means “Until then” and is often used when we know we are going to see someone again. It is easy to understand if you think of the expression “Until we meet again” which is quite formal in English but the intention is similar.

Bis Morgen! This literally translates to “Until tomorrow” and is used when you are going to see the person again the next day or soon thereafter. A simple example is when you leave the office for the day and you say “Bis Morgen!” to your colleagues on your way out the door. The funny thing is that Germans often take you literally. So if you say this to someone you most certainly will not see tomorrow, you often get an explanation of why you will actually not be seeing them tomorrow!

Mach’s gut! This does not translate into English very well, as directly translated it means “make it good”. It can be loosely translated as “Take care” or “Have a good one” and is used informally amongst friends.

With all of the options above, you will no doubt be able to greet someone and say good-bye in German.