First add relationship to ApplicationUser
public class ApplicationUser : IdentityUser
{
public string Name { get; set; }
public string Surname { get; set; }
public IList<Address> Address { get; set; }
}
and then you call call it easly using UserManager Class
var user = await userManager.Users.Include(x => x.Address).SingleOrDefaultAsync(x => x.Id == Id);