“得” is extremely common in daily life. Its usage is strictly divided by its pronunciation.
This is a formal and written usage, often found in set phrases. In daily conversation, 得到 (dédào) is more common for “to get”.
This is the most common use of 得 for beginners. It has no tone and is always placed after a verb.
This is a very common spoken word for obligation, similar to “gotta” or “have to” in English. It's more colloquial than 必须 (bìxū).