Instead of copying and pasting the data, Airtable offers you the ability to import an Excel file directly into a pre-existing table. You can just right-click on the table name and choose to import data from an Excel file.
However, you would need to have the Excel file accessible on your desktop or in a cloud storage space… you couldn’t just import the contents of the Excel file while it is sitting in an attachment field.
Is there a reason that you’re storing the Excel files in an attachment field first before importing the data? I’m assuming that you’re doing this because non-collaborators might be submitting these Excel files via a form?
There is no automated way in Airtable to automatically download an Excel file from an attachment field and then import its contents to another table.
But if you’re looking for an automatic way of doing it, you could automate that entire process by using the Airtable & Excel functions of Make, which is a low-code automation platform:
That would probably take me at least 45 minutes to setup (or much longer, depending on the complexity of your specific situation), so I can’t give you the exact step-by-step instructions here.