A unicode heart is a symbol that can be used in a text by typing a specific code on the keyboard. For example, codes for a heart in unicode include "U+2665" and "U+2764." The method of input depends on the operating system of the computer being used and keyboard layout.
Unicode is a technical standard used in the computing industry to manage characters like letters and symbols in writing. It was developed in conjunction with the Universal Character Set to standardize rules surrounding character input and creation. Unicode includes characters from various alphabets, numbers, punctuation, mathematical symbols and shapes. Full lists of characters and their codes are available on various websites.