Copy & Paste Keyboard: Create WordBoard Keys From The Clipboard
You can create keys without leaving the app you're typing in.
- Copy some text or an image, or select some text.
- In the WordBoard keyboard, tap the ⊞ button in the bottom left.
- Choose Add Clipboard to save what you copied, or Add Selected to save the selected text.

Copied images become image keys. New keys go into the folder you have open in the keyboard.
The same menu has Open App to jump to WordBoard.