How and where is this possible?
It is not possible!
Both Lightroom Classic and Photoshop are only available by a subscription to a Creative Cloud Photography plan, paid monthly or annually.
You may still be able to buy Lightroom v6 (perpetual), but support for this has ended. It will not get updates or new cameras added.
It is still possible to purchase Lightroom 6. It costs $79 in the US for an upgrade or local currency price. Go to this link:
The price of the full version is normally shown at the check-out but you can use the pull-down menu to switch to the cheaper upgrade price if you already own Lightroom 5 or an earlier version. Lightroom 6 is the final perpetual licence and it is no longer being updated by Adobe. So be aware that as modern operating systems get updated there is a risk it could become redundant.
If you wish to remain completely up to date and have support, if needed, its best to subscribe to one of the photography plans starting at $9.99pm or local currency price. You can only sync to the cloud & mobile devices with a subscription
I want to buy a Lightroom Classic licence without any cloud storage and with a one-time payment. How and where is this possible? Same for Photoshop Classic.
It isn't. No more perpetual licensed versions of LR.