How to bold title of text box widgets

Please provide a link to a page on your site where we can see this. Thanks.

From my test site:

https://www.chicagostaycation.com/about/

Would like to bold “FIRST SECTION #1” & “SECOND SECTION #2” of each text widget.

h3.widgettitle.widget-title {
    font-weight: bold;
}

To add CSS:

• If you are using WordPress 4.7 or later, use the “Additional CSS” option in the customizer.
• If your theme has a custom CSS option, use that to add the CSS shown above.
• If not, install the plugin Simple Custom CSS.

Learn to use the Chrome Developer Tools to help you see and test changes to your CSS.

Worked perfectly via “Additional CSS”, thanks so much!