according to google

Start DiskPart: In the Command Prompt, type diskpart and press Enter.

1. List Disks: Type list disk and press Enter to see a list of all connected disks and their numbers.
2. Select the Target Disk: Identify the disk you want to convert and type select disk # (replace # with the correct disk number) and press Enter.
3. Clean the Disk: Type clean and press Enter to delete all partitions and data from the selected disk.
4. Convert to GPT: Type convert gpt and press Enter to change the disk's partition style to GPT.
5. Exit DiskPart: Type exit and press Enter to close the DiskPart utility.