tapinput allows entering any character with 2 taps, though you might need to
change 'mode' first to get upper case.
One a 3x3 set of keys, tap the key that show the symbol you want, then
wait a moment and all the keys will change to show a single symbol.
Then tap that symbol to enter it to the focus window.
Once you understand the pattern, you can tap twice without waiting for the
keys to redraw.
In number mode (123) only a single tap is needed for digits.
To get '*' and '#', hold '0' for a moment, then tap which symbol
you want.
The window can be moved by simply dragging it. If it is moved more than
half off the display, it will disappear.
The window is activated by pressing the keyboard icon in the dock.