How do i use possessive nouns for two people in a sentence?

To use possessive nouns for two people, you typically add an apostrophe and "s" to the second person's name if they share ownership, and to both if they own separate items. For example, "Jessica and Mark's car" indicates they share one car, while "Jessica's and Mark's cars" shows they each own their own car. Ensure clarity by structuring the sentence based on the relationship between the nouns.