Meaning
A smooth wavy line borrowed from Japanese writing, where a wave like this can stretch a sound or add a playful emphasis. As an emoji it simply works as a long, wavy dash.
People use it to stretch words and add a sing-song mood, much like a tilde, or as a decorative divider in bios and lists: “Weekend is finally here〰️” It also suggests something fluctuating, like a wobbly mood. It is easy to confuse with ➰, which loops instead of waving.