Quick, clean, and to the point

Drag to duplicate worksheet

Windows shortcut 
Mac shortcut 

Normally, when you click and drag worksheet tabs at the bottom of a workbook, you are reordering the tabs. Use this shortcut when you want to duplicate a worksheet. The cursor will change to a small plus (+) sign inside a document. When you release your mouse, a copy of the worksheet will be inserted at the location of the cursor.

Excel foundational video course
Excel Pivot Table video training course
Excel formulas and functions video training course
Excel Shortcuts Video Course
Excel Charts video training course
Video training for Excel Tables