Location: Administration >> Configuration >> Blocks
The blocks configuration page allows you to manage installed blocks and their settings.
This number tells you how many times a particular type of block is used in the courses on your Moodle site.
Some blocks can be added multiple times to the same course. This of course is supported only by blocks for which it makes sense. For example, it makes sense to have two HTML blocks (and configure each one to show something different), but it doesn't make sense to have two Administration blocks. For those blocks which do support multiple instances, the administrator can choose to allow it or not.
To delete a block click here and it will be removed from Moodle. However you will need to use a file manager and remove/delete the actual module directory from the moodle/blocks directory, otherwise Moodle will reinstall it next time you visit the admin page.
Adding a non-standard block
You may add non-standard blocks simply by using a file manager to copy the new block as a directory into the moodle/blocks directory and Moodle will install it next time you visit the admin page. Moodle uses the name of the directory as the name of the block. The same applies for blocks which you delete and wish to reinstall later.