What is the name given to something that does not add information in a sentence?

It sounds like you want descriptive words. If so, adjectives are what describe something in a sentence.

PLEONASM is the use of more words or parts of words than are necessary or sufficient for clear expression: for example black darkness or burning fire. Such REDUNDANCY is, by traditional rhetorical criteria, a manifestation of TAUTOLOGY.

However, pleonasm may also be used for emphasis, or because the phrase has already become established in a certain form.

[ Source: en.wikipedia.org/wiki/Pleonasm ]