"å hete" is a verb. This verb is in other languages like swedish, danish and german. It is used to indicate names. It's like the verb to call(å kalle noen(/noe) noe). If you are going to use "å kalle noen(/noe) noe" for names for people, then you should do it on Nicknames.

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"Jeg heter" is basically "I'm/I am", whilst "Mitt navn er" is "My name is" and sounds quite formal.