Hash email addresses are created using hashing algorithms such as SHA-256 or MD5. When an email address is hashed, the algorithm processes the email address and generates a unique string of characters. For example, hashing the email address "example@example.com" using SHA-256 might produce a string like "9d4c2f636f067f89cc14862cbd17b4d513f4f730cdfd092b3e3a7e4e1b9e42cd".