Win 10 pro MBR TO GPT

I,m sorry if this has been posted before .

I managed to secure erase my Samsung evo 850 m.2 250GB SSD then reinstalled windows using the official Microsoft tool . I don't know how but the disc is now MBR so wont allow me to use secure boot UEFI . I understand that the disc needs to be GPT to boot from UEFI settings . How do I convert the disc to GPT . I don't mind a reinstallation as I have a full back up of personal files .

Thanks

Had a look at your link and I,m sure the options would work for some . I decided to go back into my BIOS and found that I had the wrong settings . I had legacy enabled , UEFI and secure boot disabled so when the system found the USB boot disc it must have formatted the drive MBR . Changed back to UEFI and secure boot and made the first boot device USB . At set up I deleted the drive and re-created anew s imple volume and reformatted and the installation went ahead creating some system partitions and I had my GPT drive back .

Thanks for your help