Welcome to the Community space, Tom.
You can create additional company files in your QuickBooks Online account by buying another subscription, and I'm here to guide you on how.
You can visit the QuickBooks pricing page and select the subscription option you want. Go to the login page and click on the Sign in next to the Already have an Intuit account? option. Use the same login credentials you have for your current company. If you prefer to use a different set of credentials, you can enter a new user ID.
After setting up your new company, you can invite users to your company file and grant them specific access.
If you need additional concerns about creating an additional company file, please leave a reply below. I'm always here to help you.