This example is based on the ‘Five Star Business Profile and Schema’ plugin.

The icons in the example are WordPress ‘dashicons’: https://developer.wordpress.org/resource/dashicons/

Add the icons to CSS Classes like this:

.bp-phone:before {
content: "f470";
}
.bp-directions:before {
content: "f230";
}
.bp-contact:before {
content: "f466";
}
.bp-booking:before {
content: "f145";
}
.bp-opening-hours-brief:before,
.bp-opening-hours .bp-title:before {
content: "f469";Code language: CSS (css)

Then wrap the text in a <div> or <span> with a class like this:

<div class="bp-phone">
<a href="tel:+31618385549">06- 1838 5549</a>
</div>Code language: HTML, XML (xml)

If it doesn’t work, then you also have to declare the font in the CSS

.bp-phone:before { font-family: dashicons; content:"f525"; }
.bp-contact:before { font-family: dashicons; content:"f466"; }Code language: CSS (css)