Back up any important files from the pendrive
Insert the pendrive into your computer
Open File Explorer on Windows or Finder on Mac
Locate the pendrive in the list of drives
Right-click the pendrive and select Format on Windows
On Mac, open Disk Utility and select the pendrive
Choose the file system you want, such as FAT32, exFAT, or NTFS
Select Quick Format if available and desired
Confirm the format action
Wait for the process to complete
Safely eject the pendrive after formatting