This is the headline feature. When you buy a PC, the C: drive often takes up the entire disk. If you want to create a separate D: drive for data, Windows native tools (at the time) were useless. EASEUS allowed you to "shrink" the C: drive and create a new partition in the unallocated space, all without losing data.
No. Do not run this on a Windows 10/11 machine with important data. The risk of data corruption due to outdated drivers is high. This is the headline feature
You will see a classic two-pane layout:
Assuming you have obtained the EASEUS_PM_5.5.1_Portable.zip file: This is the headline feature