Well, if you are talking about their house, like "I am going to the Smiths' house", then yes, and it is possessive and the apostrophe comes after the plural noun ("Smiths"). But you aren't addressing it to the house. If you are inviting their physical house to the shower, then you could address it to "The Smiths' House."
Otherwise, go with one of the other options.
This. I you are referring to Mr. and Mrs. Smith as the hosts, then it is Smiths. If you are referring to the party being at the home of Mr. and Mrs. Smith, then it is the Smiths' home.
If their name is Smith and not Smiths, then it should be Smith's. Not Smiths'. At least that's what I remember from my editing classes!
Sorry, but no. It belongs to more than one Smith, so it's plural (Smiths), then it's possessive, so the apostrophe goes after the possessive (Smiths'). It would be Smith's if it only belonged to one Smith.
All very confusing to me. I have to contend with a name similar to "Hess"...and always go with the Hess Family if I can get away with it because I never know where to put the apostrophe when it includes both husband and wife and it is plural as well.
Re: Apostrophe question
Even if it's their house? I thought that would make it possesive since it's the Will's house? I appreciate your help.
This. I you are referring to Mr. and Mrs. Smith as the hosts, then it is Smiths. If you are referring to the party being at the home of Mr. and Mrs. Smith, then it is the Smiths' home.
Sorry, but no. It belongs to more than one Smith, so it's plural (Smiths), then it's possessive, so the apostrophe goes after the possessive (Smiths'). It would be Smith's if it only belonged to one Smith.
I am thinking the home belongs to the family Smith. Singular. So I would opt for Smith's
Now off to research!
BUT I agree with the above that just says no apostrophe is you are saying
The Smiths if the format is
The Smiths, Address
The Smiths'
This is always funny and helpful:
https://theoatmeal.com/comics/apostrophe