Rules for making family names plural (in greeting cards, newsletters, invitations, and so forth):
Add "es" to make most names that end in "ch," "s," "sh," "z," and "x" plural:
- Have you heard from the Birches?
- The Joneses invite you to dinner.
- The Lashes can't come this year.
- Season's greetings from the Alvarezes.
- The Foxes flew to Hawaii.
Add "s" to make names that end in "y" plural:
- The Kennedys throw a great holiday party.
Never use an apostrophe to make a name plural! Apostrophes are for possessives. (Grammar Girl Tips)
