If you're still trying to decide whether or not to take Portfolio during Summer term 2018, the deadline to apply is May 26. It will be here before you know it!
There are prerequisite actions that need to be completed and cannot often be done instantaneously. The most important one is completion and submission of your Application for Admission to Candidacy (AAC). Please refer to the Steps to Graduation for details on how to proceed, both with the AAC and applying for Portfolio using the online form. Other important considerations that will need to be satisfied are, 1) all core courses need to be completed, at a minimum, prior to taking Portfolio and 2) taking a final elective concurrent with Portfolio is strongly discouraged.
Registration for Portfolio for Fall 2018 is also still open, but closes on August 17, earlier than for regular University courses, due to the fact that late submission of prerequisite documents can create serious issues with the Graduate College and the fact that software needs to be purchased for the course and the headcount of registrants needs to be stable...maybe more than you wanted to know, but just to let you know we're not just being capricious.
As always, feel free to contact me if you have any questions or concerns...I'm happy to help!