End a singular noun with an apostrophe ‘ followed by an “s”
If you don't the noun will be a plural noun (yes that means the writing is wrong)
Wrong - The tigers paws were stuck in the mud.
Correct - The tiger's paws were stuck in the mud.
Wrong - Both of Kaylas children are good skiers.
Correct - Both of Kayla's children are good skiers.
https://owl.english.purdue.edu/owl/