SET was created and written by David Kennedy (ReL1K), and it is maintained by an active group of collaborators (www.social-engineer.org). It is an open source Python-driven framework that is specifically designed to facilitate social engineering attacks.
The tool was designed with the objective of achieving security by training. A significant advantage of SET is its interconnectivity with the Metasploit framework, which provides the payloads needed for exploitation, the encryption to bypass antivirus, and the listener module, which connects to the compromised system when it sends a shell back to the attacker.
To open SET in a Kali distribution, go to Applications| Social Engineering Tools | setoolkit