what is a possessive pronoun that could replace these words

Question

1.Martha Katz's (before a noun)

1.Martha Katz's ( not before a Noun)

Answer 1

You'd need to put those in sentences for us to know what you're expected to do.

Generally, "her" and "hers" are the 3rd person singular personal pronoun forms to show possession.

Answer 2

write thepossessive pronouns that could replace each group of words what is

a noun and not before a noun
Martha Katz's