Question

When an author repeats words or phrases to draw attention to an idea?

Answer 1

Usually this is just called "repetition"!

But some more fancy terms for different types of repetition are:

Anaphora, which is repetition at the beginning of a clause or sentence.

Some less common cases are an epistrophe, which is repetition at the end of a sentence or clause, and a symploce, which combines both anaphora and epistrophe, meaning that it is repetition of the same phrase at the beginning AND the end of a sentence or clause.