After a person passes away, the custom is that the deceased's sons say Kaddish for him during the proceeding eleven months for his Eliui Neshama.
In the Yeshiva website, we have various Shiurim regarding this topic. Rabbi Eliezer Melamed summarizes the Halachot of the mourner's Kaddish, Rabbi Daniel Mann discussing the issue of sharing the right of saying Kaddish, and Rabbi Yirmiyohu Kaganoff explains the origin of this custom, and how does it help the deceased.
In addition, the rabbis on the website answered various questions regarding kaddish and especially the mourner's Kaddish. Rabbi Gideon Weitzman discusses the custom of reciting kaddish for people who had no children, Rabbi David Sperling addresses the issue of answering Kaddish in the middle of a prayer, and Rabbi Ari Shvat answers the question regarding charging a fee for saying Kaddish.
Sometimes a situation arises where a person passes away and has no sons who can say Kaddish for him. To help people who are in this situation, the Yeshiva website provides a special service of reciting Kaddish for the deceased by a Yereh Shamayim Ben Torah, who will recite Kaddish for the eilui neshama of the deceased.
This service is given to the donors of the Yeshiva website. The donors will have a Ben Torah who will recite Kaddish for their deceased relative, and also, at the same opportunity, take part in spreading the Torah to hundreds of thousands of learners through the Yeshiva website in the zechut of the deceased.