this code is from your ocr demo
TMSMCPCloudAI1.Context.Text := 'extract the text from the picture';
TMSMCPCloudAI1.AddFile(fname1, aiftImage);
my test with pdf is this:
TMSMCPCloudAI1.Context.Text := 'extract the text from the pdf document';
TMSMCPCloudAI1.AddFile(fname1, aiftPDF);