According to the Bible, How Are You Actually Married in God’s Eyes? Sex? Ceremony? License?

Hebrews 13:4

Over the years, I’ve often been presented with the question, “I had sex with someone, so are we now married in God’s eyes?” Similarly, I’ve also been asked, “Aren’t marriage ceremonies and marriage certificates simply man-made ideas? Can’t two people just commit themselves before God and be married in God’s eyes?”