There is a functionality for injecting css into the screenshot. 

However, The font needs to be stored somewhere in the cloud. In our example we used google fonts: (See photos below for reference)

 
 
 

 

For the example screenshot above, we used this CSS:

 

@import url('https://fonts.googleapis.com/css2?family=Splash&display=swap');
body
{
font-family: 'Splash', cursive;
color:blue !important;
}
h1,h2,h3,h4,h5
{
font-family: 'Splash', cursive;
color:red !important;
}

 

All headings or at least some of them should be appear with the custom font "splash" and a different color. 

I hope you find the above information useful!