Excel macro that runs the file is opened

Are you asking how to trigger a macro when a workbook is opened?
If so right click on the small Excel icon in the left hand top corner of your workbook (next to File). Choose View Code from the list. Set the left hand dropdown to Workbook and the right hand drop down to Open. Now writ your code.
Hope this is what you want

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By naming the macro

Sub auto_open()

it will automatically run the macro when the sheet is opened.