You can use my, your, his, her, its, our, or their to show belonging.
You can also use a person's name and add 's to the end.
You can use 's instead of my, your, his, her, its, our, or their.
You can use a proper noun or a common noun.
This is my sister's backpack.
This is my friend's backpack.
This is my teacher's backpack.