Many people see marriage as having two key purposes:
Marriage is a civil contract between two people.
The couple to be married may choose whether to have the ceremony in a register office or other place licensed to conduct marriages. They may also choose to have it as part of a religious ceremony in a place of worship licensed to conduct marriages.
In 2014, the UK parliament brought in a law known as the Marriage (Same Sex) Couples Act 2014. This law allowed couples of the same sex to get married in England, Scotland and Wales - although the law excludes same-sex couples getting married in church.
Increasingly, couples are choosing to live together before deciding whether to get married. Some couples choose to live together without ever getting married. Living together without being married is called cohabitation. Opinions on this vary within and between different religious traditions.