OD.WebApplication/OD.WebApplication/Models/HomeViewModel.cs

using System.ComponentModel.DataAnnotations;
using System.IO;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.FileProviders;

namespace OD.WebApplication.Models
{
    public class HomeViewModel
    {
        [Required]
        public IFormFile FileAttach { get; set; }
    }
}