Tabs in Salesforce represent different tables where data is stored. You can modify the tabs you see to meet your business process needs. To customize the tabs you view, following these instructions from Salesforce Trailhead:
1) Click the Plus Icon
Click the Plus icon to the right of your current tabs. The All Tabs page appears. By default, it shows all tabs you have available to view or add.
2) Click Customize My Tabs
In the Custom App drop-down list, select the app where you want the tab to appear. For example, if you want the Scholarships tab to appear on the David Eccles School of Business app, select David Eccles School of Business from the drop down.
3) Add, Move, and Save Tabs
To add / remove tabs or change their order, use the Add, Remove, Up, and Down arrows. Any tabs listed under Selected Tabs will be visible on your layout. If you do not see a tab in the Available Tabs section, please contact your program's Salesforce liaison. Be sure to click the Save button when you are finished.