Hi,
Seems you are using custom module for the donation, as you need to change the PDF report, either you can directly change inside that custom module or you can create a new module and inherit the template and apply the changes.
If you are not into technical and need to do it from the user interface, activate the developer mode and navigate to Settings -> Technical -> . .. -> Reports, search for corresponding report and open it. Then in the top right of screen you will see the button to access the templates of this view and you can edit and change it.
If you need to do from the code side as a new custom module, see how to inherit and make changes in existing reports in odoo: How To Inherit And Modify Existing PDF Reports in Odoo
Thanks