Visa vs. Resident Card?

What is the difference between the two? In this reddit it seems to be used synonymously.

Im trying to figure out steps to take to change my status from student to "cultural activities" (doing research but not being paid by a Japanese university or institution). I found a page for instructions to change resident status but would I need to change my visa in my passport as well or is it all the same thing?

Thank you!

by SqueakyMoonkin