You might want to look for an add-on for this.

Although Firefox has a feature to export your bookmarks to an HTML file which you could view in Firefox and copy from or print as with any other web page, it only shows the descriptive text and not the website address, so I suspect that isn't going to be very useful.

If you want to try to work with the built-in features, I suggest:

(1) Export your bookmarks to an HTML file; save it in a convenient location such as your Desktop or My Documents. This article has the steps: Export Firefox bookmarks to an HTML file to back up or transfer bookmarks

(2) Open that HTML file in Firefox as a web page. You can double-click it (if it has a .htm or .html extension), or drag and drop the file onto an open tab, or use the menu: tap the Alt key > File menu > Open File.

(3) Locate the portion of the file you want to print, and select it. Do not print from Firefox because the selection printing generates needless blank pages. Instead, copy the selected bookmarks and paste into a blank word processing document or new email message to yourself. Then you can print from there.

1. Click the Bookmarks button and choose Show All Bookmarks.
2. In the Library window, click the Import and Backup button.
3. Choose Export Bookmarks to HTML and save the file somewhere handy, like the desktop.
4. Drag and drop the file you saved onto the Firefox window to open it.
5. To print all of it, click the ≡ Menu Button, then the Print button.
   • To print only a part of it, select the text with the mouse, then hold down the Ctrl key and press P (Mac: Command+P).

Export Firefox bookmarks to an HTML file to back up or transfer bookmarks

Drop down to DOS. Find that directory. Then in the DOS window, type Dir <full folder name> The Greater Then ">" Now decide. Do you want to print this ( type PNT ) or do you want to save the information ( type full path and file name ) Then press enter.