SSL certificates are small data files that digitally bind a cryptographic key to an organization's details. When installed on a web server, they activate the padlock and the HTTPS protocol and allows secure connections from a web server to a browser. SSL certificates provide a secure connection between a web server and a browser, ensuring that all data transmitted between the two is encrypted and secure. This helps protect sensitive information such as credit card details, login credentials, and personal information from being intercepted by hackers. Additionally, SSL certificates help build trust with website visitors by displaying the padlock icon in the browser's address bar, indicating that the site is secure and their data is safe.