Yes, you can type /resign when it is your turn to end the game.

Thanks. The keyboard input should only show up if your browser is indicating there is a soft keyboard available for the device. On Android, the device keyboard doesn't work for some reason. It definitely shouldn't show up on desktop, though. I will look into this.

The desktop version[0] shouldn't have this issue, if you want to give that a try.

0. https://bgammon.org/download/