1. Open your workbook.
2. Click on "File" on the ribbon.
3. Then click on the "Options" menu at the very bottom of the menu bar.
4. Click on "Customize Ribbons" to customize your ribbon and tabs within it.
5. Then click on "New Tab".
6. From the left side of the list, click the function you want your tab to be part of, and click on "Add>>".
7. Say, you want "Font" to be part of your tab. Click on "Font" and then "Add>>". It will appear on right side of the list within your "New Tabs" section. You can do for more functions as well.
8. Then rename your new tab by clicking on "New Tab(Custom)" and then on rename.
9. Enter the desired name for your tab. Say, Harshal's Tab.
10. Hit on OK.
11. Hit on Ok again and your tab has been renamed.
12. Now, as is visible your ribbon has been customized, click on your new set tab and you will be able to see the functions that you included. You can change the functions by repeating the same.