Visualforce
Visualforce is a web application framework developed by Salesforce for building custom user interfaces that integrate with the Salesforce platform. It uses a tag-based markup language similar to HTML, combined with a server-side controller written in Apex, to create dynamic, data-driven pages. Visualforce pages can be embedded within Salesforce applications or accessed as standalone web pages, enabling developers to extend and customize the Salesforce user experience.
Developers should learn Visualforce when building custom applications, portals, or complex user interfaces within the Salesforce ecosystem, as it provides a native way to create tailored solutions that leverage Salesforce data and logic. It is particularly useful for scenarios requiring advanced UI customization beyond standard Salesforce configuration, such as creating customer portals, custom dashboards, or complex data entry forms. However, note that Salesforce is increasingly promoting Lightning Web Components (LWC) as the modern alternative for new development.