Use multiple Excel sheets on one app?

Example: I was playing around with the Inventory template and wondering if I made a app similar to this to let my customers subscribe to the app. Is it possible for the different customers to have their own Excel sheets with their data on a local computer? And then connect those to one app? The thought behind this is that every customer has total control of their data.
My apologies if this is a stupid question. I have only been on the Glide platform for a couple of days

No, this is not possible with Excel. It would be possible with Glide Tables, but each customer would need their own App. For example, when you get a new customer, you could duplicate the App, and the table along with it. Then you simply rename the new App and the new Table to match that customer.

When using Excel, if you duplicate an App, the data gets converted to a Glide table for the duplicated App.