How to Delete or Minimize Web Parts in SharePoint 2013
You have two options for removing a Web Part from your SharePoint page — closing or deleting. Closing a Web Part leaves the Web Part on the page so you can enable it again for future use. Deleting the Web Part removes the Web Part from your page (but doesn’t delete it from SharePoint).
To close or delete a Web Part from your page, click the Web Part menu, and choose Close or Delete.
When you want to add a closed Web Part back to the page, you find a category in the Web Part Gallery called Closed Parts. Clicking the Closed Parts category reveals all the Web Parts on the page that have been closed. On the other hand, if you delete a Web Part, it will be gone forever.
If you spend time configuring a Web Part and want to remove it, it’s better to close it so that you don’t lose all your configuration changes. Keep in mind that having a closed Web Part on a page causes the same performance impact as if they were open. So you don’t want a ton of closed Web Parts if you don’t need them.