I already have a quickbooks account, what is the best way to open up another account for my other business?

I have a way to allow you to open another account for your other business.

You can create or add another company file to your QuickBooks Online under the same Intuit account. Here's how:

1. Visit the QuickBooks pricing page and choose the subscription option you prefer. 
2. Once on the login page, click the Sign in link next to Already have an Intuit account? and use the same credentials as your current company. If you prefer to have separate credentials, enter a new user ID. 
3. Follow the on-screen instructions to create a new company file.

For detailed information, refer to this article: Create or add another company file to QuickBooks Online.

You can visit this article to learn how to switch between companies: How do I switch companies?

Thank you for considering QuickBooks Online for your business needs. We hope this information helps you as you manage your multiple businesses. If you have any further questions or need assistance, feel free to reach out to the Community forum. We're here to help you succeed. Best regard!