How to Encrypt a USB Flash Drive Using Bitlocker
How to Encrypt a USB Flash Drive Using BitLocker
1) Insert the USB flash drive into one of the laptop’s USB ports.
2) File Explorer may open automatically after inserting the USB flash drive. Otherwise, open File Explorer by clicking File Explorer icon 
at bottom of laptop screen.
3) Right click on “USB Drive” (see picture above) and select "Turn on BitLocker".
Follow the instructions to set the BitLocker code (password) and encrypt the USB flash drive.
4) Check the box for “Use a password to unlock the drive” and enter the password you want for the USB flash drive.
5) Click “Print the recovery key”.
6) You can print the recovery key and hang onto the paper for later use, if needed, or select “Microsoft Print to PDF” to store the recovery key in a PDF file.
7) If the USB flash drive is new or unused (e.g., it doesn’t contain any files), then select “Encrypt used disk space only (faster and best for new PCs and drives)” and click the “Next” button.
8) If the USB flash drive is already used (e.g., contains files), then select “Encrypt entire disk (slower but best for PCs and drives already in use)” and click the “Next” button .
9) Select “Compatible mode (best for drives that can be moved from this device)” and click the “Next” button.
10) Click the “Start encrypting” button.
11) Click the “Close” button when finished.
12) Afterward, when you insert the USB flash drive in your computer (laptop), you will see this pop-up window to enter your password.