Judaism teaches that mourners should perform certain mitzvot to honor the memory of deceased family members. These mitzvot include giving charity, studying Torah and reciting Kaddish. Kabala teaches that saying the Kaddish prayer on behalf of the deceased memorializes and helps elevate the soul of your loved one in the world to come.
It is customary for mourners to recite Kaddish three times daily with a minyan for 11 months after the death of a parent, or 30 days for other immediate family members. It is also recited annually on the yahrzeit (Hebrew calendar anniversary) of a loved one’s death.