When making a word possessive, add an apostrophe and an s. If a singular or plural word ends with an S, do not add an extra S.
- The donut thief ate Sam’s donut.
- The donut thief ate Chris’ donut.
- The donut thief ate the managers’ donuts.
Apostrophes can also be used to denote that you’ve dropped some letters from a word, usually for humor or emphasis. This is fine, but do it sparingly and always tailor it to the tone of the client or subject matter.