Hi marney23,
Welcome to Apple Support Communities. We understand that you're having an issue with exporting data to a PDF from Safari. We'd like to help.
From what you've described, it sounds like this resource would be helpful to you:
If an app freezes or quits unexpectedly on Mac
If you still have issues after that, testing this behavior in safe mode may resolve it: How to use safe mode on your Mac. This will check for errors and try to resolve them so testing in this mode, then restarting your Mac will be helpful.
Finally, testing to see if this issue happens in another user account on your Mac will allow you to know if this is device wide or specific to your user. If needed, you can Set up users, guests, and groups on Mac to test in a new user.
Hope that helps. Keep us updated on how that goes.
Take care!