How to activate Visualforce pages in Lightning experience in Salesforce community?

Hi,

Visualforce pages must be enabled for mobile use before they can display in these areas of the Salesforce user interface:

• The navigation menu, via a Visualforce tab
• The action bar, via a custom action
• Mobile cards on a record’s related information page
• Overridden standard buttons, or custom buttons and links
• Embedded in record detail page layouts
• Lightning pages

1. To enable a Visualforce page:
2. From Setup, enter Visualforce Pages in the Quick Find box, then select Visualforce Pages.
3. Click Edit for the desired Visualforce page.
4. Select Available for Lightning Experience, Lightning Communities, and the mobile app then click Save.

Consider these notes about Visualforce support.

Standard tabs, custom object tabs, and list views that are overridden with a Visualforce page aren’t supported. The Visualforce page is shown for full site users, but Salesforce app users will see the default Salesforce page for the object. This restriction exists to maintain the Salesforce app experience for objects.
You can also enable Visualforce pages for the Salesforce app through the metadata API by editing the isAvailableInTouch field on the ApexPage object

Hope this helps.