My ultimate goal is a Webapp for Permit Data. In the pop-up I want the permit # to have a hyperlink to the permit application. Do I set that in my feature layer in Desktop or in my web map or wait until I make the webapp? I'm a bit confused on how to set up the attribute. I don't want to copy and paste thousands of applications to each individual permit #. Is it possible to set something that once they click on the feature, the correct application will come back in the hyperlink? I think I would choose script from the Hyperlink menu but unsure after that.
Advanced logic for hyperlinks can be managed using Arcade expressions. Getting Started | ArcGIS for Developers
What logic do you want to apply? If it is simply a URL including the value of a field permit, no need to use Arcade. This can be achieved using a custom pop-up window.