Am I able to link a form with an excel sheet?

On the sales form, could I link the item sold to an inventory excel list?
Will it automatically deduct from our inventory? 

You can link the form submission data to an Excel sheet.

User guide: How to Create an Excel Report

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Will it automatically deduct from our inventory?

This process can be achieved outside the form. You can do it instead using the Excel application.

You can review the following similar discussion threads.

https://www.jotform.com/blog/221-Connect-Your-Forms-to-Excel-with-Zapier

https://www.jotform.com/answers/373071-Integrate-Jotforms-with-Excel

https://www.jotform.com/answers/1272758-How-to-use-a-form-to-manage-inventory

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