Highlight higher value of different cells

Ioannisd 

Let's say the data are in B2:B50, D2:D50 and F2:F50.

Select F2:F50.

Hold down Ctrl and select D2:D50.

Still holding down Ctrl, select B2:B50.

You should now have selected all three ranges, with B2 as active cell.

On the Home tab of the ribbon, click Conditional Formatting > New Rule...
Select 'Use a formula to determine which cells to format'.
Enter the formula

=B2=MAX($B2,$D2,$F2)

Click Format...
Activate the Fill tab.
Select a highlight color.
Click OK, then click OK again.