I would like to add a Tag line to the header under my logo. I am using the Integrity stack. I didn’t see an option to add a tag line in customization but I figure it would be possible to put in some text under the logo and have it centered with the use CSS to control the font, color and look of it.
The easiest way is to add it using CSS. Place the following code into your Customizer, Custom > CSS section using the menu Appearance -> Customize and replace the tagline content:
a.x-brand.text::after {
content: "This is your tagline";
display: block;
font-size: 1.4rem;
letter-spacing: 1.2px;
}