How to use Visualforce page in Salesforce community cloud?

1. You must enable "Available for Lightning Experience, Lightning Communities, and the mobile app" for a Visualforce page to make it available in the Lightning App Builder.
2. Add <apex:slds /> in the VF Page.
3. On the Community Profile page, click Enabled Visualforce Page Access and add the Visualforce page.

1. Go to Community Builder.

2. Drag and Drop Visualforce component to the page and add the Visualforce page.