controller.cs

public class FileController : ControllerBase
{
    private readonly IConfiguration _configuration;
    private readonly ILogger<FileController> _logger;
    public FileController(ILogger<FileController> logger, IConfiguration configuration)
    {
        _logger = logger;
        _configuration = configuration;
    }
    [HttpPost]
    public async Task<IActionResult> Post(IFormFile file)
    {
        var uploadStream = file.OpenReadStream();
        using (var fileStream = System.IO.File.Create(Path.Join(_configuration.GetValue<string>("OutputDirectory"), Guid.NewGuid().ToString())))
        {
            await uploadStream.CopyToAsync(fileStream);
        }
        return Ok();
    }
}