Click on grayish bars scroll to My Profile click on it Scroll to My Story Then you can type in your bio I hope this is helps for you 💜

Click on 3 lines and click on my story

As Tracy said that there’s another step in between which is click on my profile

I tried to update my story, but when I hit save it says, Error: Invalid Data. ?? What am I doing wrong?

Just click on the 3 gray lines on the upper right corner.
Click my story. then profile. I hopes that this helps.