Your grades this semester will automatically be Pass/Fail, unless you visit the above website by May 12th. Exceptions past this date will not be made so make sure to get your selection in by that date.
As a reminder - taking the default pass/fail is 100% okay, and in fact, I encourage you to use that option. If you know that a letter grade will increase your GPA, by all means take it, but otherwise I would recommend sticking with Pass/Fail. A Pass will suffice to fulfill major requirements and a notation regarding COVID-19 will appear on all student transcripts.
As a reminder, you are not merely learning online, you are at home, during a crisis, trying to learn. Have patience and compassion for yourself.