Always here to help Ruchi :)
>>can you teach me how to make a D drive from my drive
You need to shrink the C drive to create a new volume. In the disk management, right-click C:, choose to Shrink and enter the amount in MBs you want to shrink the drive, i.e. the size of D. When shrink is done, right-click the unallocated space>New Simple Volume>NTFS.
Shrink Volume or Partition in Windows 10 | Tutorials (tenforums.com)
>> I heard that media creation tool makes it so that u can boot both jn legacy and uefi bios?
No, that is not correct. MCT makes the media according to the device it was run on. If you are sure that the system on it ran uses Legacy boot, that is fine.