You must include all your family members even if they are not coming to Canada with you. This includes:
spouse or partner
dependent children
dependent children of dependent children (grandchildren)
Also, for you to become a permanent resident, all your family members must pass a medical exam and background checks even if they are not coming to Canada with you.
If you don’t include all of them:
you could be refused entry into Canada, and
you may not be able to sponsor the family members you didn’t include in your application to come to Canada at a later date.