Answer:
An appositive phrase is when you add another name or title to a noun. It looks something like this:
Ginger, my cat, is named Ginger.
The appositive phrase is the "my cat", because you already know that I'm talking about Ginger, but the "my cat" provides more information.
Appositive phrases/words are always right next to the noun they are helping desrcibe, and can use commas like my cat example, or not.
Anyways, they're used to help describe nouns and give more context and information about that noun without sounding like this:
Ginger is named Ginger. Ginger is my cat.
I hope this helps!