Use apostrophes to form verb contractions (we're for we are; let's for let us) and to make a noun possessive:

  • Singular nouns: add 's, even if the word ends in s (device's, boss's)
  • Plural nouns that don’t end in s: add 's (people’s)
  • Plural nouns that end in s: add an apostrophe (customers’)
  • Singular proper nouns or names: add an 's, even if the name ends in s (Amit Singh's phone; Susan Jones's workspace)
  • Plural proper nouns or names: add -es for names ending in s or z and add 's for everything else (the Joneses' computer, New York's subway system

Don't use an apostrophe with the possessive pronouns his, hers, ours, yours, and theirs

In particular, take care not to confuse it's (contracted form of it is or it has) with its (possessive pronoun).

It's important to maintain a logical order in your modules.
Its important to maintain a logical order in your modules.

Don't turn nouns into contractions, as they can be hard to translate.

Planning is easier with Anaplan
Planning's easier with Anaplan

Avoid forming a possessive of any Anaplan product name, trademarked or not.

Our Hyperblock engine enables multi-dimensional scenario modeling.
Hyperblock's engine enables multi-dimensional scenario modelling.

As always, if the use of an apostrophe in your sentence makes it look or sound awkward, try rewriting it. 

For any other specifics on possessive apostrophes, refer to the AP Style Guide.