Shortcut key for changing code cell to markdown cell in jupyter notebook

Press M whilst in command mode (highlight around the selected cell should be blue, not green), use Esc to switch to command mode and Enter to switch back to edit mode.

So, if you're editing a cell, the key presses to change the cell to a markdown cell are Esc, M, Enter.

You can look up all the Jupyter notebook keyboard commands by pressing the keyboard icon in the toolbar. You can also edit your keyboard shortcuts by going to Help > Edit Keyboard Shortcuts

check help on the menu, there is keyboard shortcuts

select the code cell, press "esc + m ",and it will be a markdown cell. moreover, from markdown cell to code cell, press " esc + y ".