What should I write in my portfolio?

HI folks,

This might sound like a dumb question but please bear with me. I’m currently building my portfolio page that I plan on hosting as a github page (hopefully). I’ve just about finished the whole site but now I am at that point where I have to write an about me section and I am pretty stuck. Do I write some sort of personal essay? Should I stick to the relevant job experiences and credentials? Do I try to write/make something unique? What do typical code portfolio’s say about the author?

Thanks in advance for your input.