web application – A3 and WEB certificates

Hello, I know you have some questions related to the subject, but I have not been able to draw any conclusion (at least from the ones I have read), in short, is it possible to apply A3 digital certificates (for authentication and / or signature) in WEB applications?

I have read some answers where users say that it is possible to use A3 in a web application as long as you have an application installed on the user, if that is viable someone has some material on?