You can use Session to pass a value from one to another page, in your case create session and store all required values while the login like

Session["taxPayer"] = "Tax Payer Name";

And you can get the tax payer name from your needed page, like

string taxPayerName= Session["taxPayer"];

Finally close your seesion,

Session["taxPayer"]  = null; 

(OR) 

Session.Abandon(); //Close all sessions