Hello team,
I wish you are Well.
My question is : how can i Open an Excel file from Camunda form ? i want to click on a path and then Open an excel file with Office.
thank you
Are you suuure you want to do that? 
I hate to even recommend the approach because you’re bound to run into issues along the way (it’s a slippery slope).
I can’t imagine there being a “Camunda way” of doing this, but strictly from an HTML perspective, you could accomplish this for the most part with protocol handlers. Office registers it’s own when you install Office and they’re kinda documented here. So, in theory, you could embed a link in your form that allows the browser to prompt the user to open the link in Excel, granted the document is available locally or via URL and that the user has MS Excel installed. For example:
<a href="ms-excel:ofv|u|https://contoso/Q4/budget.xls">Budget</a>