Mixing licence types

I have a laptop and a PC. The PC is configured with a free license. I understand that I need to purchase a license for the laptop.
Can I purchase 1 pro license for the laptop and configure both to use the same email address?

Not necessarily. If you don’t need the Pro features, you can register a separate Free licenses for the laptop. Just be aware the Free licenses can’t be used for anything other than personal home use, so you can’t use either device for business.

Yes, as long as your use is not for business. If you use eM Client for business, you will need to purchase Pro licenses for both devices.