A prepositional phrase is a group of words that lacks either a verb or a subject, and that functions as a unified part of speech. It normally consists of a preposition and a noun or a preposition and a pronoun.Prepositional phrases can act as adverbs or adjectives. When used as adjectives, they modify nouns and pronouns in the same way single-word adjectives do.When used as adverbs, they at the same way single-word adverbs and adverb clauses do, modifying adjectives, verbs, and other adverbs.

Example :
1. The cupcake with sprinkles is yours. ( with sprinkles )
2. We climbed up the hill. ( up the hill )
3. The rabbits hopped through the garden.( through the garden )