Drupal 7 has many powerful components to retrieve and store your custom data. Such custom data could be Car Models, News Items, Calendar Events, School Courses, a Yahoo Answers Question and Answer commentary board, a Product Showcase, etc. The core pieces of Drupal that help to define this data and the pieces that comprise them are Entities and Fields. When we make a Content Type Drupal presents the user with a generic CRUD interface generated from the FieldUI. How can we customize these types of input forms to better suite your client? How can we optimization their presentation, and interaction?
To answer these questions we can look to Drupal Core functions, and then Community Modules built to enhance core Drupal functionality.
Drupal Core Functions Learn More