Add Tab on Lightning Page

Lightning pages use tabs to organize data on the screen.  You can add / remove tabs as you organize your data from viewing.

New tabs can display related lists, report charts, basically any object available in Lightning Builder.

To Add a Tab in Lightning Experience: 

1. Have a record open on the page you want to set the default tab.
2. Click the Gear (Setup) button and choose Edit Page. Find the section that contains the tab headings and select it.
3. Click the Add Tab By default the Details tab will be added.
4. Click on the Tab in the list and choose the Label from the list. Click the Done

**Only the tab has been added  the page.  You can now click and drag any object from the list on the right (e.g., report chart, related list, etc.)

5. Click on Save and Activate to save the changes.
6. Click on Back to return to Salesforce with the new default tab.

Follow the above steps on any page you want to add a tab.