Can I run two businesses with separate books in my subscription?

You can use the Search bar at the top of any page, here in the community, to find answers to most questions.  In doing so, I was able to find a thread that I believe best answers your question. 

https://quickbooks.intuit.com/learn-support/en-us/reports-and-accounting/can-i-run-two-separate-businesses-with-qbo/01/416270#M44393

@Jennifer529 

One QBO account is for one company file. You may manage branches/divisions by utilizing the Class/Location feature available in QBO Plus and Advanced. Otherwise you should open a new account.

https:// quickbooks.grsm.io/US

https:// quickbooks.grsm.io/us-promo

Businesses 

1 Login quickbook

2 Greer icon (Setting option)

3 Select Setting and account option

4 Go to Advanced option 

5 Select Categories option and select business option 

6 Activate business option and Click Save option And Done

Second Step 

1 Greer icon (Setting option)

2 Select All list option 

3 Click business option 

4 Create Business list