ParkerD;6464381:
Not quite correct. If two people happened to be living together as a couple then they would certainly need to be married (civilly) before they would be considered ready to be baptized and become members. But of course many single people become members, and some stay single their whole life and they are welcomed always as official members in good standing. (But the lay leadership are usually married, except in developing nations where that may not always be the case.)
When I was a missionary in Honduras, most adult couples were not married. We could not baptize them until they were married. We often paid for their weddings (civil) if they could not afford it.
An endowment means a special gift of power to resist temptation plus a special covenant with God that is taken very seriously.
It is, or at least was, also a blood oath.
To clarify again, marriage in an LDS temple is considered very important, but not “essential” to be a “covenant member of the church.” It would be when the couple are ready to make solemn promises to each other and to God that are eternally binding promises, which they seriously intend to keep throughout their life and throughout eternity so those covenants are extremely important, and need to have been prepared for.
However, when I was LDS, I was taught that, in order to attain the highest level of heaven, one must be married. I doubt I would have gotten married back then if not for that doctrine. Also back then, Men pledged to obey God, women pledged to obey their husbands.