Hi, I just took a look - in your theme it’s in Theme Settings. Go to Apps > Translate & Adapt > Theme Settings > Logo and you’ll see it. However note that you don’t currently have other languages (Settings > Languages).
On images containing numbers - I see your use case and yes you could do that with an image. But broadly having text you might want to select, like numbers or email addresses, is best as text rather than embedded in an image. But these things are totally your choice.