How can passoutput parameters in stored procedure

CREATE PROCEDURE [dbo].[spSMSLogin]
(
@USERID NVARCHAR(50),
@PASSWORD NVARCHAR(50),
@ISVALID BIT OUTPUT,
@PID NVARCHAR(50) OUTPUT
)
AS
SET NOCOUNT ON;
BEGIN
SET @ISVALID = 0
IF EXISTS (SELECT 1 FROM UserInfo WHERE UserID = @UserID AND Password = @PASSWORD AND IsActive = 1)
BEGIN
SET @ISVALID = 1
SELECT @PID =PID FROM UserInfo WHERE UserID = @UserID AND Password = @PASSWORD AND IsActive = 1
END END