Build web app with expense submission, expense review, and finance tracking functionalities

We are interested in developing a web app that will allow us to automate a lot of the administrative tasks we need to do to carry out our work. The app will serve three main functions: 1) Provide a simple and easily accessible interface that will allow users to submit expense information that will be automatically stored in our organization's Google Drive. 2) Allow for admin to review this information and engage in a dialogue with the user if necessary. 3) Track all expense data in an organized way to a) allow users to view project expense summaries and b) allow admin to create and generate expense reports. Attached is an overview of how each interface should articulate with the others as well as a detailed summary of what each interface could look like. Note that the details here are not comprehensive and questions are expected, but the general shape is there. Note that these interfaces will need to effectively and seamlessly articulate with one another as well as external systems like Quickbooks.