Learn how to format hard drive and remove all partitions using windows tool called DiskPart to clean / remove / delete all partitions in a disk or hard drive. This command line (diskpart) also works on USB drive.
If the “clean” command in diskpart does not work, try “clean all” command (which is an alternate to “clean”), which will remove all the files on the disk including partition information and will take a very long time to process. “Clean all” will make data recovery slightly difficult (but not impossible). To ensure data is not recoverable, use the command “Eraser” to clean the disk several times.