Hi Attar Dasthagir,
If you want to send an attached document to the organizer via Mail,
You can achieve this by using two approaches. The first thing is, you able to give the document file in the Email template which already as you configured in the email template configuration page via administrator. But the same file will send to every organizer via mail.
The second thing is if you want to send an attached document to the organizer which the player uploaded in the system, You can follow as Eline Bijkerk said a solution to your question. It will work.
Hope it helps!
If you're using the e-mail module, it has an entity called “Attachment” that is a specialization of FileDocument. You can use that to attach the filedocument in question to the e-mail before sending it:
You can find an example of how to use attachments in the excluded example flow “Sub_CreateAndSendEmail”.