question

When installing Windows on UEFI-based PCs using Windows Setup, your hard drive partition style must be set up to support either UEFI mode or legacy BIOS-compatibility mode.
You cannot use 2 together.

Ref:

Windows Setup: Installing using the MBR or GPT partition style

Ref:
Need to make a choice between MBR and GPT

BIOS vs. UEFI
Both BIOS and UEFI are standards that PC motherboard's firmware must follow.
UEFI uses a completely different boot mechanism than BIOS. Old booting techniques that were used with BIOS don't work with plain UEFI anymore, but there's the Compatibility Support Module (CSM) - an optional component of UEFI which provides backwards compatibility with BIOS booting. This old boot mode is called legacy boot in UEFI setup programs.

If you want to boot into UEFI BIOS using your current MBR-partitioned HDD, you'd need to reformat it to GPT. Otherwise, you're stuck with booting only into Legacy BIOS. When installing Windows on UEFI-based motherboards using Windows Setup, your hard drive partition style must be set up to support either UEFI mode or legacy BIOS-compatibility mode. Obviously, you've used to the latter and that's why it has MBR partition table.

Here's a Microsoft document you can refer to regarding the installation of Windows using the MBR or GPT partition style:
https://technet.microsoft.com/en-us/library/dn336946.aspx?f=255&MSPPError=-2147217396

If the Answer is helpful, please click "Accept Answer" and upvote it.
Information posted in the given link is hosted by a third party. Microsoft does not guarantee the accuracy and effectiveness of information.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

@SSengupta-4080 and @TeemoTang-MSFT

Thank you for explaining about GPT and MBR.

Previously my laptop had GPT partitions. For reinstalling Windows 10, I created bootable flash drive using rufus and selected Partition Scheme GPT. During installation, there was an error; GPT disk partitions not in recommended order .. .

One of Tech guy, converted GPT partition into MBR using diskpart during installation process.
And used his own bootable flash drive. He only said, GPT is not required.

After installation, when I plugged in my bootable flash drive, it is showing in two parts in This PC
Moreover, I checked partition type in diskpart. It is showing GPT.

That's why I could not understand.

Please elaborate and clarify confusions.

With Regards
NndnG

You'd better ask for help from the tech guy who installed system for you, he will tell you why he did this.
If you create two partitions on your USB drive, it will show two parts in Explorer, it is normal.
For UEFI-based device, you must format the hard drive that includes the Windows partition by using a GUID partition table (GPT) file system
https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/configure-uefigpt-based-hard-drive-partitions