This character is a Other Symbol and is commonly used, that is, in no specific script. The character is also known as lips.
The glyph is not a composition. Its East Asian Width is wide. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. U+1F48B offers a line break opportunity at its position, except in some numeric contexts.
The CLDR project calls this character “kiss mark” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: dating, emotion, heart, kiss, kissing, lips, mark, romance, sexy.
This character is designated as an emoji. It will be rendered as colorful emoji on conforming platforms. To reduce it to a monochrome character, you can combine it with Variation Selector-15: 💋︎ See the Emojipedia for more details on this character’s emoji properties.
The Wikipedia has the following information about this codepoint:
A kiss is the touching or pressing of one's lips against another person, animal or object. Cultural connotations of kissing vary widely; depending on the culture and context, a kiss can express sentiments of love, passion, romance, sexual attraction, sexual activity, sexual intercourse, sexual arousal, affection, respect, greeting, peace, or good luck, among many others. In some situations, a kiss is a ritual, formal or symbolic gesture indicating devotion, respect, or a sacramental.
The word comes from Old English cyssan ('to kiss'), in turn from coss ('a kiss').