Sunni and Shia are both fundamental practices in the Islamic faith, both united in many of their beliefs; however, there is a clear divide that began centuries ago regarding who should succeed Prophet Muhammad as a leader of the Islamic.
Sunni Muslims believe that it was the right decision to have someone who was most capable of doing the job, while Shia Muslims believe that the successor should have come from within the family of the late Muhammad. Sunnism is the leading and most orthodox branch of Islam.
Now, concerning Nikah, Shia Muslims believe in Mutah or marrying a woman for a brief time while Sunni Muslims do not believe in this ritual, which has been forbidden by the prophet. There are also differences in their religious practices, but only by a small measure.