Boxing stance tends to have lead leg forward and rear leg behind with a narrow stance shoulder width or less. Your lead shoulder and rear shoulder 
should be inline that is your medial deltoids of the lead shoulder is facing your opponent. This makes sprawling harder.
The differences between the stances of various combat sports is staggering. Here are a few difference amount Kickboxing, MMA, and Boxing. This doesn’t include wrestling which is quite different than these.
Kickboxing Stance
A kick boxing stance would have legs farther apart, more than shoulder width and your more squared off to your opponent. Your lead shoulder and trailing shoulders should form a 45degree angle to your opponent whereas the boxing stance is is perpendicular.
Boxing Stance
The easiest way to see the difference is to first stand in boxing stance, perpendicular to opponent then move your trailing leg out until it becomes parallel with your right shoulder.
MMA Stance
The mma stance varies but can nearly parallel to you oponent, both shoulders facing your opponent.
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