[SalesForce] Not able to give CRUD permissions to custom object on Customer Community Plus Login User Standard Profile

1. You need to create tabs of that object which you want to give Access on community.
2. Give the accessbility of tabs and object on profile level.
3. Go Your Name-->Setup-->Customize -->Community-->Manage Community. Then click on Edit link. Then a pop up will appear and then click on "Tabs nad Pages" tabs and add your tabs into seleted part.

I would check the following for the tab to be visible:

1. The profile has read access to knowledge
2. The profile has the tab either Default On or Default off
3. Enable to read permission for the article types you want top share on the profile
4. You added the tab to the community
5. You selected edit profiles and activated the profile on the detail page
6. You assigned the correct profile to the user
7. The profile has access Knowledge One checked (App Settings)
8. They have access to the data category