1. Home Controller:

    public class HomeController : Controller
    {
        private readonly ILogger<HomeController> _logger;
        private readonly IServiceRepository _servicerepo;
        private readonly IHttpClientFactory _httpclient;
        public HomeController(ILogger<HomeController> logger, IServiceRepository serviceRepository, IHttpClientFactory httpClientFactory)
        {
            _logger = logger;
            _servicerepo = serviceRepository;
            _httpclient = httpClientFactory;
        }
        [HttpPost]
        public async Task<string> AddFileItemAsync(FileItem _fileItem2, IFormFile _file)
        {
            var httpClient = _httpclient.CreateClient("httpclient");

            using (var multipartFormContent = new MultipartFormDataContent())
            { 
                multipartFormContent.Add(new StringContent(_fileItem2.ID.ToString()), "ID");
                multipartFormContent.Add(new StringContent(_fileItem2.Name), "Name");

                // Add the file
                var fileStreamContent = new StreamContent(_file.OpenReadStream());
                fileStreamContent.Headers.ContentType = MediaTypeHeaderValue.Parse(_file.ContentType);
                multipartFormContent.Add(fileStreamContent, name: "file", _file.FileName);

                //// Method 1 : this method returns Unsupported media type, but if file is removed then it works fine.
                //var response = await httpClient.PostAsync("/api/todo/SaveFileWithData", multipartFormContent);

                // Method 2 : this method also returns Unsupported media type, but if file is removed then it works fine.
                var request = new HttpRequestMessage(HttpMethod.Post, "/api/todo/SaveFileWithData");
                request.Content = multipartFormContent;
                var responsemsg = await httpClient.SendAsync(request);

                responsemsg.EnsureSuccessStatusCode();

                var response = await responsemsg.Content.ReadAsStringAsync();
                return response;
            }
        }

2. AddFileItem view page:

    @model MVCWebApplication.Models.FileItem

    @{
        ViewData["Title"] = "AddFileItem";
    }

    <h1>AddFileItem</h1>

    <h4>FileItem</h4>
    <hr />
    <div class="row">
        <div class="col-md-4">
            <form asp-action="AddFileItem"  enctype="multipart/form-data">
                <div asp-validation-summary="ModelOnly" class="text-danger"></div>
                <div class="form-group">
                    <label asp-for="ID" class="control-label"></label>
                    <input asp-for="ID" class="form-control" />
                    <span asp-validation-for="ID" class="text-danger"></span>
                </div>
                <div class="form-group">
                    <label asp-for="Name" class="control-label"></label>
                    <input asp-for="Name" class="form-control" />
                    <span asp-validation-for="Name" class="text-danger"></span>
                </div> 
                   <div class="form-group">
                    <label >File:</label>
                    <input type="file" name="_file" class="form-control" /> 
                </div>
                <div class="form-group">
                    <input type="submit" value="Create" class="btn btn-primary" />
                </div>
            </form>
        </div>
    </div>
 3. API Controller:

    [Route("api/[controller]")]
    [ApiController]
    public class TodoController : ControllerBase
    { 
        [HttpPost()]
        [Route("SaveFileWithData")]
        public async Task<string> SaveFileWithData([FromForm]FileItem? fileItem, [FromForm]IFormFile? file)
        {
            int i = 2;
            return "fileSavedSuccessfully";
        }
    }

4. Program.cs file: Configure the httpClient.

builder.Services.AddHttpClient("httpclient", http =>
{
    http.BaseAddress = new Uri("https://localhost:44374/");
});