Could I access to the content fields if I publish a component? In the table CustomMetas I can see all the fields I add in the MetaData component. I can not get the fields I add in the content tag?
Tridion Content Delivery does not expose the content fields, it exposes something called a "Component Presentation", which is the result of rendering the components with your Component Templates.
A very common approach for fully dynamic application models (like DD4T) is to render the content of the component as structured data (using XML or JSON) and then loading/parsing this on the delivery side.
Short answer: no, you don't see the individual
Content fields of your component, but you can render your components to output structured data instead of html.