Now, if for some reason you cannot do this, or if your file is in 2013 or 2014 version, contact Intuit QuickBooks so they can assist with it. Support is included! Go to http://intuitcar.es/contactquickbooksonline then click View Contact Options then Call.
If you need to setup more than one company, you will need to set up a new subscription for each one. It means you will need to pay additional charges (NOT FREE) for setting up new subscription. They may offer some discount for adding new subscription.
You can use the same login name/ username for all the companies. When you log in you will get a list of the companies you have access to.
Simply go to http://quickbooks.intuit.com/
and sign up using the link “Already have an Intuit user ID?”
Select “Switch Company” under Your Company heading
It will take you to login screen with the following messages:
Our records show that you have access to more than one company, or multiple users in the same company. QuickBooks Online Companies
futureqbo (example) Canceled Companies