Is it possible to create multiple accounts within the application?

In summary: no...The Household Accounting Book is designed as a simple to use application to manage your income and expenses with a minimal learning curve for the user to be able to operate it.
If you want to maintain multiple accounts, manage taxes and more sophisticated functionality, we suggest you use other applications that are out there (e.g. quickbooks, quicken etc.).

However, if you have different users setup on your machine and you install the software for "Everyone", every Windows User will be able to keep his/her own Household Accounting Book...