Can I create a second company in QB or do I have to signup for a new subscription? My 2nd company is small can I export/import only this data to a new QB account later?

If your 2 companies use the same tax reporting ID then , if you have Plus version, you can use Class Tracking to separate the books between the 2 operations. Otherwise you probably need a second subscription. They can both be different versions but all attached to your one intuit account. There is no QB provided 100% failsafe export import to from QBO and definitely not directly between QBO companies although there may be third party apps that will work.