both people; the two of them
Refers to two people together, often in formal or written contexts. More formal than 二人 (ふたり).
両人とも無事で何よりです。
I'm relieved that both of them are safe.
契約書に
The contract requires the signatures of both parties.
両人 is a slightly old-fashioned, formal term for 'the two persons' similar to 両氏, but it lacks the honorific nuance tied to using surnames or titles.
Compound of 両 (both) and 人 (person).