When comes to development in Salesforce, we have two approaches.
Declarative denotes the point and click approaches. Examples can creating a table, fields standard page layout, work flows, approval processes etc.,
Programmatic denotes the approach that requires coding to provide a solution. Salesforce provides two different programming languages such as Visualforce and Apex to enable developers to implement the solution that may not be possible in declarative way. Visualforce is a mark up based language (like HTML) used to create custom pages and Apex is a OOPS based language used to write business logic.
Comparison between Declarative and Programmatic approaches.
The table above shows declarative requires less maintenance compared to programmatic. This requires you to understand both the approaches. To know more about MVC, Visualforce and Apex, please refer the other pages in this site.