Redirecting http to https

How does treepl handle redirecting http to https?
(ie. Is this automatic, do we need to check a box setting somewhere, do we need to contact the treepl team to set this up, etc…)

It seems to automatically do this in test sites under domain *.treepl.co
so is it just the same when a site goes live with its custom domain?

Yep, it’s https by default.
You need to contact support if you DON’T want https (but this causes issues accessing the admin).