How do I customize my button?

How do I remove the black border from around my button? I would prefer it be gone, but if it has to stay, then let's make it the same color as the primary button color. Also, how do I change the color of the button once depressed from dark teal to my color of choice? Lastly, after I press the button, it says "Please wait" - how do I turn that off, or at least change it to something else that renders better in that small space?