Why isn't there a name tag changer Uno and friends?

[Windows Central Question]

Why isn't there a name tag changer; Uno and friends

I've played uno and friends for a while, but I can't change my username. At first, I thought you had to have a Facebook account,but my friend got it, and he can change his username any time he wants. I'm e doesn't even have a change username button. Anyone else know if I can fix it?