GoAffPro provides you with the option to set up the sources from where you want to auto approve affiliates.
To set up sources to auto approve affiliates from, go to the Advanced section of the Settings tab in the GoAffPro admin panel.
Here, go to the Auto approve affiliates from section.
Now, enter the utm_source from where you want the affiliates to get automatically approved.
After this, click on Save.
The utm_source set here is Facebook, which would mean that affiliates coming from Facebook will be automatically approved.