Hi @PennyP
Of course you can add an attachment to an approval email.
The following step is for your reference:
'Get file content' can be found in many connectors, like sharepoint, onedrive, file system.

The result of the flow in Outlook is:

If you still have the problem, please feel free to let me know.
Best Regards,
Community Support Team _ Kira Xie
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.