に限らず is used to say that something is not limited to the thing you mention; it applies to other things as well. You often pair it with a contrasting statement like も, でも, or にも to show the breadth. For example, you might say 'This restaurant is not just popular with locals, but also with tourists.' It sounds a bit formal, so it fits written Japanese, speeches, or polite conversation, not casual chat with friends.

The noun can be a person, place, thing, or even a verb in plain form. When you use it with a verb, it often implies 'not only when doing X, but also...' For instance, 'not only when running, but also when walking.' Just remember that the noun or verb form goes right before に限らず, and then you add the extra information with も or にも.