Pi-Hole dockers

how to set up a pi-hole block page in dockers, thanks

It's well defined, here: https://hub.docker.com/r/pihole/pihole/

Sorry, but I had already seen it, but I can't see where it is, how to configure a custom page for when a site is blocked.

nobody knows? any suggestion?

The block page is of very limited value, since it is only served for http pages (not for https). There are very few http pages on the internet.

The block page will be dropped in a future version of Pi-hole.