The bonus to doing this, other than the satisfaction of eternal love and commitment, is the Ring of Mara. A prompt will appear for both players, and, if agreed upon, they will float in the air briefly, and then be married.
Once there, have one person equip the pledge by dragging it onto their action bar, turn, look at their companion, and initiate the ritual. Pair up with whomever you wish to marry, and visit a Shrine to Mara in any of the major starting towns. The Rings of Mara item needed for the Ritual of Mara.
Currently, only players who have the Rings of Mara, currently found only in the Imperial Edition, can get married.
