Apple Watch Keyboard

If you want to change from scribble to keyboard on your Apple Watch, you can do so by swiping up from the bottom of the screen and tapping on the Keyboard button. This will bring up the keyboard so that you can type instead of using the scribble feature.

You're welcome.

Exactly which model Apple Watch do you own? The keyboard is only available on Series 7 and newer. With WatchOS 8 or newer.

Then you cannot use a keyboard, because that model does not support it.