Hello,
I would like to join the testing of your app on TestFlight, but I need an invitation code. Kindly please send me the TestFlight invitation code if possible.
Thank you very much!
As explained in your other post - and, please don't raise multiple posts for the same thing; it just clutters the forums: You're in the wrong place. Contact the developer of an app directly if you want a TestFlight code. It's pretty obvious.