On the iSeries, you can just type in GO PTF from a command line and bring up the menu to Load, Apply, Order, etc…
There is a lot that can be done. The processes that you will use will depend on many variables.
To get some background on the possibilities and to locate some details that might be helpful for you site, review the topic Using software fixes in the Information Center. You might need to search for the Info Center for your release for some details.