Answer:
Both forms are used when making words possessive. In possessives, the placement of the apostrophe depends on whether the noun that shows possession is singular or plural. However, if the word is pluralized without an s, the apostrophe comes before the 's. So, the difference between putting the apostrophe before the 's or after the s' changes the meaning and usage of the word.
Step-by-step explanation:
Apostrophe before 's:
It is used for mainly singular words for eg. teacher's book, cat's food. But if the word is pluralized without an s, the apostrophe comes before the s, for eg. men's clothes, women's jewellery, children's toys.
Apostrophe after s':
It is used for the plural words for eg. dogs' house, boys' action.