Supplementary information includes adverbs and things that function as adverbs.
Literal
Supplementary-information [to-には], adverbs [and-や] adverb [genitive-の] function [object-を] doing things [subject-が] enter.
A linguistics/grammar instruction sentence. 補足情報 (ほそくじょうほう, 'supplementary information') and 副詞 (ふくし, 'adverb') are technical terms. はたらき ('function, role,' from the verb 働く) is used here in the grammatical sense. 入ります ('enters / goes in') is a slightly metaphorical use — information 'enters' a category. The や particle marks a non-exhaustive list.