How to change site title in child theme?

I’m using the Child theme AgentPress2 which has a simple built in editing section to change my site title. I have noticed that competitor websites (real estate) have managed to add some very specific key text that become the purple google links and aren’t necessarily the name of their websites. When you google my url, the site name shows only as my name. How can I edit this to chose some specific (relevant) keywords but not change the homepage site name?

Thank you!

https://www.JeanMarieVeegh.com