Golf is open to all
Making a stroke on the putting green - Making a stroke while standing across line of play
You must not make a stroke from a stance with a foot deliberately placed on each side of, or with either foot deliberately touching, the line of play or an extension of that line behind the ball.
For this Rule only, the line of play does not include a reasonable distance on either side.
Penalty for Making Stroke in Breach of Rule 10.1: General Penalty.
In stroke play, a stroke made in breach of this Rule counts and the player gets two penalty strokes.