How to assign claim identity role to user queries

[miss786]

Dear all, I am writing to seek help, what is the process of creating a claim identity model, to assign role/name to queries. the queries below, output to sets of users and I would like to know, how can I assign role/name to them using claim identity, if possible.

public UserDetail trial_test(string username, string password)
{

       var query = from s in db.Subscriptions
                        join u in db.UserDetails on s.sUID equals u.uID
                        where s.s\_ExpiryDate >= DateTime.Now &&
                        s.sPID.Value == 163 &&
                        s.sAll.Value != true &&
                        u.uUsername == username &&
                        u.uPassword == password
                        select u; 
            return query.FirstOrDefault(); 
        }
        
    
    public UserDetail full\_test(string username, string password)
        {
            var query = from s in db.Subscriptions
                        join u in db.UserDetails on s.sUID equals u.uID
                        where s.s\_ExpiryDate >= DateTime.Now &&
                        s.sPID.Value == 163 &&
                        s.sAll.Value == true &&
                        u.uUsername == username &&
                        u.uPassword == password
                        select u;
            return query.FirstOrDefault();
        }

Thanks in advance.