What you make and how you make it: process, materials, decisions and outcomes.
Practice research, reflective writing, documentation, peer critique.
The longer story
In practice research the object of study is, at least in part, your own work: the things you make, the way you make them, and what happens when other people meet them. This is the usual situation for artists, designers, composers, performers and writers doing a doctorate.
It changes the usual picture of research. You are both the investigator and part of what is investigated, so documentation and reflection carry a heavy load, and you need a way to show that the findings are more than personal preference. Terms vary (practice-based, practice-led, practice as research, artistic research) and institutions define them differently. Check which one your regulations use.