The difference between a clause and a phrase can simply be defined by identifying a subject and a verb; a phrase usually doesn't have a subject-verb component.
Here is an example of a clause and a phrase:
(Independent Clause) I love her.
(Phrase) With the right money.
Straus, Jane., Kaufman, Lester and Stern, Tom. The Blue Book of Grammar and Punctuation. 11th ed. San Francisco, Jossey-Bass, 2014.