Microsoft Office applications have been designed with touchscreen devices such as tablets in mind

 

You can enable touch mode in Excel to optimize all the buttons/toolbars to make them easier to click when using a touchscreen device

 

To enable this feature click on the down arrow next to the quick launch toolbar (as circled in red below) and click on Touch/Mouse Mode

 

N.B. This first step may not be necessary as on some devices it automatically detects touch input and enables this option

 

 

This will then display a new button on the quick launch toolbar (as highlighted in red below) where you can switch between Touch and Mouse mode

 

 

The images below show the difference between Mouse mode and Touch mode for the Home ribbon - notice how all the buttons are spread out more so you can easily point to them with your finger