Can I add a second business that I own to my QB account?

One QBO account is for one company file. You can use QB Desktop to manage multi company files.

I can help you add another company to your QuickBooks Online account, jared29.

To set up another company, you'll need to create a new QuickBooks Online account because each company file requires a separate subscription.

Also, you can link an additional company to your existing email address by logging in to your current company account while creating a new one, and then click on Add another company.

Here's how to do so:

1. Visit the QuickBooks pricing page and select the subscription option you want for your new company.
2. a. Choose the plan you wish to have.
   b. On the Sign-in page, enter your email address.
   c. Click the Create a new company button. 
   d. Follow the prompts to finish creating the account. 
    

Additionally, refer to this article to learn how to manage multiple company files: Create or add another company file to QuickBooks Online. 

Once the account is created, you can easily switch between companies. Refer to this guide on how do I switch companies for additional information on changing companies seamlessly.  

Let me know if you have any further questions about adding a new company. I am willing to help at any time.