Besides their name are rubbermaid products patented PLEASE HELP? read bellow and answer ?

What can you patent and not patent? In other words if rubbermaid makes plastic cups how do their competitors make plastic cups? I have heard you can patent a process. So pretend that I John Deer makes a lawn mower. If they patent that process how does Sears make theirs? Can you patent a process like that? What processes can you patent?