The shortcut for the pen tool is "P".
Pressing "X" will will switch from fill to stroke and pressing Shift + X will change the stroke and fill colour around.
Pressing / will make the colour null (not there) depending on which part you have active (stroke or fill).
When using the pen tool, if you need to go from a bezier curve to a corner, use the pen tool and click on the last anchor point. The pen wool will show a lil angle icon.
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