Step 1 - Open Disk Management and right-click partitions on a GPT disk, and after that, select "Delete Volume."
Step 2 - To confirm, click "OK."
This process needs to be repeated for every partition on the GPT.
Step 3 - Once you have deleted all the partitions, now, right-click the GPT disk and choose "Convert to MBR."
After this, you can install the Windows system on the converted MBR, and also you can create the new partition.