How can I type accented characters using a physical keyboard on Xbox One?

Hi! I'm Rostom, an Independent Advisor. I will be glad to help you here.

Have you tried using these shortcuts here on this link https://support.microsoft.com/en-us/topic/keybo... ?

Really? When i saw those accents i was hmm that's weird at first i thought it was a glitch not only letters pop up accents when holding down on them also numbers have accents too as well

Yea, their all apart of the accent or international keyboard system. You can actually do this similarly on a regular computer keyboard, for more information I'd encourage you to take a look here: https://sites.psu.edu/symbolcodes/windows/codealt/ Start
with "Letters with Accents" but you can explore a few other related topics there.

Yes you can use SmartGlass as keyboard. Open keyboard on your Xbox One console, and it also opens keyboard automatically in SmartGlass. When I need to type something, I always use SmartGlass.

You may be looking at their "real names", which are set to publicly display in their profile.

You can type any character in any language depending on your keyboard settings (e.g.

Windows 10). Your real name is edited in the
Microsoft account settings.

A keyboard/mouse combo is highly unlikely. You can use USB keyboards with your xbox one to type messages and while using internet explorer