Windows 10 include a built-in functionality in Disk Management to shrink and expand partitions. No more 3rd party utilities needed! It’s worth noting that many third-party utilities will be more feature-rich, but you can do the very basic stuff in Windows without adding anything new.
To get to this utility, you’ll need to use the Start Screen search. Just use the Start Menu or the Control Panel search:
How to Extend a Partition
In the Disk Management screen, just right-click on the partition that you want to extend, and select “Extend Volume” from the menu.
On this screen, you can specify the amount that you want to increase the partition by. In this case, I’m going to extend it back to the roughly 50GB size that it was before.
Note that the extend partition feature only works with contiguous space.