How can I copy the pictures to a jump drive from a LRC file?

You don’t even have to go to the menu, you can simply click the Export button in the Library module, shown below as step 1.

Although the Lightroom Classic Export dialog box says “folder,” it really means any destination you can normally save to, including a jump drive or empty hard drive. What Bob Somrak showed is very important: In the Export dialog box, click the Export To menu, and choose Specific Folder. Then, when you click the Export button, you will be asked where specifically to save the copies, and that is where you can follow steps 2 and 3 shown below.

1. Export is an easy button in the Library panel. Click it to start.

2. After setting Export To to Specific Folder and clicking Export, you see this standard Windows file saving dialog box. To find your jump drive, click This PC.

3. At the This PC level, you will be able to see not only folders, but also a Devices and Drives section. Your jump drive will be listed here. In my example, Devices and Drives lists C and D drives, but on your computer there will be another entry for your jump drive; open that and continue.

(I have not upgraded this to Windows 11 yet, so Windows 10 is shown and might be slightly out of date.)

If the photos are imported into LrC, you would use LrC to export the photos to the Jump drive.

A question that needs vastly more information!

What Lightroom-Classic Version?

Why do you want to "copy the pictures"?

Describe the "Jump Drive".

By "LRC file" are you referring to a Catalog?

I assume you might be wanting to EXPORT derivative, edited, versions to a USB stick.

Or do you simply want to make backup copies of your 'original' camera files?