I'm not following cash out refinancing

[Cat Bauer]

I have a few single family long term rental properties and am looking at purchasing a larger commercial property. My realtor advised what most investors do is pay cash for a property, then get a cash out refi after the closing. Regardless of what is thought of this path, I'm having a hard time grasping what cash out refi is and why it's beneficial outside of tax free financing for cap ex. Could someone dumb it down a little? I'm new to commercial financing products.