How to create an internal use CRM data lookup application

How to create an internal use CRM data lookup application

I am trying to create an application which I and my team can access, put in an account number into a field and it will (if the account number exists) display the description field contents of that account.
It seemed straight forward when the idea came to me, but it's proving difficult for me to execute. Has anyone done anything similar or have ideas how I could?