Reference article: https://www.disktool.cn/jiaocheng/extend-c-drive.html
With the help of the "Partition Assistant" software, I personally tested it and it is really useful!
1. Search "Partition Assistant" on Baidu and find a safe download.
I downloaded it here https://www.onlinedown.net/soft/633400.htm
2. Open the Run Partition Assistant and find the partition adjacent to the C drive. , such as the D partition in this example, and right-click and select "Adjust/Move Partition".
3. Drag the mouse to shrink the D drive as shown in the figure below. This operation will generate an unallocated space at its head. The size can be dynamically adjusted according to the capacity of the D drive. Then click "OK".
4. In the main interface, we can see the generated unallocated space. At this time, right-click the C partition and select "Adjust/Move Partition".
5. As shown in the picture below, drag the small ball to the end, and then click "OK".
6. Return to the main interface of the software again. You will see the adjusted partition preview. Click the "Submit" button above to execute the operation of extending the C drive.
Finally, just wait patiently