What is the difference between singular possessive and plural possessive form?

Answer 1

The only difference between a singular or plural possessive is that the noun possessing something may be one (singular) or more than one (plural); for example:

Singular: The man's hat blew off.

Plural: The men's hats blew off.

Singular: My mom's meeting is at four.

Plural: Our moms' meeting is at four.

Singular: Dr. Morris' office is down the hall. or Dr. Morris's office is down the hall. (both are accepted)
Plural: The Morrises' children are twins.

Answer 2

In singular possessive form, we show that one person, place, or thing owns something. For example, "the dog's bone." In plural possessive form, we indicate that more than one person, place, or thing owns something. For example, "the dogs' bones."