Global change of font family

MeridianStyler can be used to make changes to specific elements, but if you want to make a global change of font family you can simply use the following CSS code. It goes in WP admin > Appearance > Customize > Additional CSS: 

/* primary font */
body, button, input, select, textarea, h1, h2, h3, h4, h5, h6, .post-meta-author {
    font-family: "Font Family";
}

/* secondary font */
button, input[type="button"], input[type="reset"], input[type="submit"], .button span, .styled-list, .widget-title, .widget .tagcloud a, .meridian-promo-bar, .meridian-promo-bar-close, .font-family-3 {
    font-family: "Font Family";
}

Just replace "Font Family" with the font family you want to use.