In how many ways we can pass the parameter from one VF page to Another VF page?

there are mainly two ways to pass parameters

• As url parameters . this works with any page and controller
• Other is using a shared controller (only works if both pages has the  exact same conrollers and extensions

url parameters

public Pagereference gotonewpage()
{     
     PageReference pageRef = Page.existingPageName;
     pageRef.getParameters().put('msg','success');
     return PageRef
}

shared controller

public Pagereference gotonewpage()
{     
     PageReference pageRef = Page.existingPageName;
     pageref.setRedirect(false)
     return PageRef
}