To use QB for more than one company that you are handling, there is no need to have a different copy on QuickBooks for each company. The same QuickBooks can host multiple companies. Now that there are two versions of QB, i.e., online and desktop, the process to add multiple entities is different. Since there are two versions of the software, there are two processes you can follow to open multiple companies under the same account, depending on which version you are using.