Hi @Anonymous,
Could you please share a full screenshot of your flow which could send a file?
Could you please explain more details about the go into an excel file organized with headers and data under that you mentioned?
If you would like to send an email with an excel file as the attachment,
You could create the excel file in your onedrive for business to trigger the flow, and then the flow would send an email with the excel as attachment.
You could create the flow as below:

You could also create an CSV table,and then send the email with attachment, you could create the flow as below:

Please share more details about your problem so we could provide a proper workaround for you or let me know if your problem could be solved.
Best regards,
Alice