I made cards with Solid Glass and labels, and they don’t look transparent, but dark.
Can you provide a little more details? Parameters of glass material, lighting, render settings? Maybe screenshot of issue?
Transparency distance could be a potential culprit, but like Oleksii says, it would be helpful with some more details.
Attached images are too small for my eyes, but what I see is your glass have black colour? So what strange is it looks dark?
The client wants it transparent
So make it white instead of black?