Hello flim,
Yes, you can develop for iOS without buying a mac. UE4 has built in packaging features that allows you to launch and package for iOS specifically. You are not missing any features by using a Windows machine.
Note: Having an iOS device around around so that you can test to see if the packaging worked is a good practice.
I am linking you to our documentation that steps you through the setup for developing with IOS for both PC and MAC.