I am using the Microsoft PowerApps community plan with an individual environment ,Will the data/Table I created in the Common Data Service is private or that could be open to public use ?
If the tables are accesible for public use , How can I restrict them for private use ?
No it is private and not accessible for public use.
Every Dataverse (CDS) instance comes with it's one set of security roles. Only users with proper license and role will be able to see the data in your table.