。
Every day we use many things that Edison invented.
Literal
Every-day we [topic-は] Edison [subject-が] invented many [possessive-の] things [object-を] are-using.
エジソンが発明した is a relative clause modifying 多くの物 — 'many things [that Edison invented].' The が inside the relative clause marks the subject of the embedded verb. Japanese relative clauses precede the noun they modify, opposite to English.