On the Home tab, in the Cells group, click Insert, and then click Insert Sheet.

Click plus sign button at the bottom of the worksheet tabs or right click on existing worksheet tab and select insert from the context menu, then choose worksheet from submenu.

 Select the worksheet you want to insert a new worksheet in front of, then click Insert from the Home tab, followed by Insert Sheet to insert the new workspace. ‘Shift+F11’  is used to insert worksheets in Microsoft Excel.