Microsoft has released a tool to convert from the MBR format to GPT in in order to enable users to take full advantage of the newer and more secure features built in to modern computers.
Information on the tool can be found here – https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt
Check the pre-requisites before running this tool.
MOST IMPORTANT NOTE: Make sure that your device supports UEFI before attempting to convert the disk.