I currently have the autocorrect option turned on which capitalizes the first
letter of every sentence. However, whenever I type my website in my
signature, it automatically capitalizes the first letter of the URL. For
example, I type:

Bob Smith
xyz.com

and it automatically corrects it to:

Bob Smith
Xyz.com

Is there a way to add the URL to the exceptions list so the initial letter
isn't capitalized? I've tried, but can't seem to make it work. Thanks.