You can choose the Font Family of the Text Element under the Font Format group.
If you mean changing the font of a specific text in a Text element, that is not possible and is not recommended if you want your page to be fast. That is because, you'll load the font adding up to your page load time so you're basically sacrificing page load for a small design purpose.
But, if you still want to continue, you can write HTML in a text element like this:
You can then target that HTML or tag with your custom class and that class will be styled with CSS with the font-family of your choice. You need to load the font through third party plugins or custom function. Please note that this requires an understanding of web development and you or a developer is responsible of doing this.