In Drupal, the boxes which can be made to appear in various regions of a Drupal website are called Blocks. They are an extensible core feature of Drupal with a simple API provided by the block module. Blocks are similar to "widgets" in content management systems, but are altogether generalized. Blocks can be used to present anything, so just about all content on Drupal sites other than main content, breadcrumbs, and primary/secondary menus is usually a block.
How to create block in drupal 7?
Specify pages by using their paths. Enter one path per line. The '*' character is a wildcard.
Example paths are blog for the blog page and blog/* for every personal blog. <front> is the front page.