As described here https://developer.salesforce.com/trailhead/lex_dev_visualforce/lex_dev_visualforce_intro Visualforce pages can be added as Components in the Lightning App Builder:
I have a slightly different scenario: we need to embed a Visualforce page on a Lightning Community page. Unlike in the documentation above, Communities are not edited using the Lightning App Builder, but using the Community Builder instead.
Now as an unfortunate it seems that in the Community Builder, the Visualforce component is not available under Standard nor in any other section:
Does this mean, there is no way to embed a Visualforce page on a community page right now?
Best Answer
As for now, it looks like the only option is to iframe the Visualforce page in a component.
If on Napili template, the src of the iFrame should be append by '..' as follow:
Keep in mind that this is a workaround (maybe even a hack), so be aware that it might be broken in the future, e. g. like it's going on with other workarounds. So this technique comes explicitly with an caveat emptor and you use it on your own risk.
UPDATE
We have received an info from Salesforce support:
So as for now it looks like we don't have that feature at all.