There are many sources on this. Here is one:
Making Plurals of Names
If you want to make a name plural, it follows the same spelling rule as any other kind of noun. So we write that I live next door to the Smiths. No apostrophe--no letter is left out, the word is not possessive. We would also write that the Smiths live next to the Joneses. Here -es is added to Jones because the singular word ends in an s, just like we make dresses from dress.
Smith with an apostrophe s is possessive, just like any other noun. We could say I am Mr. Smith's neighbor. That is the normal rule for making possessives. There is nothing different about it because it is a name. If Smith is plural and possessive, we would follow the same pattern that we use for any other nouns: I am the Smiths' neighbor.
Source Plurals with Apostrophes and Other Questions You Asked