This reply has been accepted as the best answer.
You need to put a class on the paragraph tag
<p style="text-align:center;" class="mybutton">
<a class="myButtonSmallTest" title="Learn About A.A." href="https://hattiesgarden.com/delivery/order/">Learn More</a>
</p>
Then add the CSS below
.mybutton {position:absolute;left:0;bottom:10px;width:100%;}
Yu also need to add a CSS property position:relative to the column rule
.widget.content-3-col {width:31%;margin:1.15%;background:grey;border:3px solid black;border-radius:10px;position:relative;}
If the button starts colliding with the text, you may need to add a bottom padding too
padding-bottom:50px;