Google Docs is a good program and since it is linked to your Gmail account, you no longer need a USB drive. But, what if you have to use a USB drive to move a document to another computer where there is no Gmail?
Steps

Step 1. Log into your Gmail account and go to Google Docs

Step 2. Find the file you want to put on the USB drive
Step 3. Once the file is open, click File> Download As …

Step 4. Select the format to which you want to convert the document
Word works very well, and RTF also gives a good conversion result.

Step 5. Save the newly downloaded file to your computer
On a Mac, click Go> Documents, and if you are using a PC, click My computer.

Step 6. Insert the USB drive into the computer's USB port
The USB drive icon will appear on the desktop or in computer files.

Step 7. Complete the operation
Just drag the document onto the USB key icon.
Advice
- Make sure to eject the USB drive after completing the operation.
- Be careful, whatever format you use.
- If you are using a Chromebook, follow this guide through 4e step, then click on the popup window at the bottom of the screen to display the files. Drag and drop the file onto the USB drive.
Warnings
- This method does not work with files in "PDF" format.
- Make sure to save the document, otherwise you may lose all your work.