Burning sage is commonly called smudging, and it can be used for a variety of purposes depending on the type being used. Smudging is generally used as a spiritual cleansing with smoke using special sacred herbs.
You can smudge a person, a place, a building, or an object. Smudging is a process that has been practiced for thousands of years in some form or another by cultures all around the world.
Smudging is normally used to remove negative energy and bring a feeling of peace and clarity. Have you ever been in a house and something just doesn't feel right? Or something just feels off about a location. Smudging the area will often remedy that "off" feeling.
There may be some confusion about what type of sage to use, so below is a short guide to help you.

