You can format a flash drive in Windows 10 using File Explorer, Disk Management, or DiskPart. The below instructions will show you how to do it using File Explorer in just a few clicks:
Open File Explorer.
Right-click your drive in the left navigation pane and click Format.
Define the format parameters and click Start.
Of course, bear in mind that formatting the USB will delete everything on it. If the USB contains data you need to keep, look at ways to format the USB without losing data.