how to get rid of your username?

You cannot remove your username, but you can change it. Your bio can be blank, just click on the space under your username and delete whatever you have in the bio section.

I tried, you can't.😎

As part of our Support Community improvement project, we’re preserving inactive posts that have historical or community value and closing them to new comments. This is one of them!

If this post covers a topic that you’re interested in discussing with the community or requests a feature you’d like to see on Khan Academy, you can try to find an active post about it and add your thoughts (or feel free or create a new post if it doesn’t yet exist in the forum).