To change default hard drive from C: to D: in Windows 11/10, change the default save location for apps and files, move user ...

Next, right-click the drive letter that you want and choose “Rename” from the right-click menu to change the letter to any other unused letter. Read: How to change Drive letter in Windows 11/10.

It is easy to do for other drives using the disk manager, but the main drive is another story. But, I figured out a method on how to do it in case anyone wants to.