On my iPad Air 3 running iOS 13.3.1, I can add funds to my Prepaid account, but I cannot add a booster. I tried several times with the same result. I can get to the booster addition screen, move the booster I want into the booster add column, but then when I click the Add button, nothing happens. This appears to be an issue specific to either iOS, iPadOS, or my particular device because I can add the booster from a Mac computer or from my Android phone. Note that the problem has nothing to do with insufficient funds; there was enough for the booster I wanted to add.