To further define, dependant child must be under the age of 22 and unmarried or have been continuously enrolled and in attendance as a full-time student in a post secondary study before the age of 22 and financially dependent on parents. The child also qualifies as a dependent if he/she has substantial financial dependence on parents since before the age of 22 due to a medical condition.
You can also sponsor a close relative that is your brother, sister, nephew, niece, grandchild who is an orphan, unmarried and under 18 years of age.