You may have been told as a kid to sit up straight and, as in most things, your mom was probably right.
Good posture is associated with better breathing, fewer headaches, better spine and neck health, and even better core muscle tone! Proper posture is when your body parts align the way that they should when using the right amount of muscle tension to support yourself.
Your ears should be aligned evenly over your shoulders, with those shoulders back and relaxed. Now that you have an idea on what good posture is, make it a habit by daily reminders and meditations to align your spine when sitting, standing, or even walking!