The possessive form for the name Adams is Adams'.
Not likely. Adams' can only be the plural possessive of the first name Adam. It is hard to imagine a proper context for such a form. If you want the singular possessive of the last nameAdams, it is Adams's, and if you want the plural, it is Adamses'.
The possessive form for the proper noun Richter is Richter's.Example: Mr. Richter's class is in room two hundred.
The plural possessive form of the last name Ellis would be the Ellises'.
The plural for the last name "Walls" is the Wallses.
Junior's
When the name of a business is a possessive noun, the possessive form doesn't change; for example:McDonald'sMcDonald's parking lotWhen a possessive noun is part of the name of a business name, but not the last word, the last word also forms a possessive; for example: Jack's SeafoodJack's Seafood's parking lot (although no one would criticize the Jack's Seafood parking lot)
The possessive form of the proper noun Mattice is Mattice's.Example: Dr. Mattice's office is in building two.
The possessive form is Lois's.This is Lois's birthday.
The plural form of the name Max is Maxes.The plural possessive form is Maxes'.Example: The two Maxes' last names are Oscar and Mayer.
The plural form of the proper noun Diaz is the Diazes.The plural possessive form is Diazes'.Example: The Diazes' children are twins.
No, you do not need to use an apostrophe in a last name if it is not possessive.
The plural form of the proper noun Charles is Charleses.The plural possessive form is Charleses'.Example: The two Charleses' last names are White and Green.