DOes mautic offer double opt in forms?

THis should be by default but then I read on this forum double opt in forms are not supported?
Is that true?

You can use segments or campaigns to mimic double opt in form flows.

See more here:

No, Mautic doesn’t offer out of the box a double optin pricedure.

I add that it should not, as how you manage the double optin is a very customized task, also if you have to do it under the rules of the GDPR/privacy laws…

You have to build your own double optin flow.