i dont know how to use this bug reporter website thing

does the username need to be your minecraft username because if it is i mightve crapped myself. pls how do you change your 'username' box in your profile section because it isnt my minecraft username and i dont know if it affects anything because my real minecraft username is InfiKnight_VIII and i dont know if having a correct minecraft username changes anything so pls tell me if having the correct minecraft username is needed to make things work or if i can just choose some random stuff for my username. plz tell me

PS not really a bug ik i just wanted to know... im a newbie here