// In ApplicationUser Table
    [Required]
    [StringLength(10, ErrorMessage = "The {0} must be at least {2} and at max {1} characters long.", MinimumLength = 2)]
    [Display(Name = "Employee Id")]
    public string EmployeeId { get; set; }

public string OtherUser { get; set; }

[ForeignKey("ApplicationUser")]
    public string? UserId { get; set; }
    public virtual ApplicationUser ApplicationUser { get; set; }