How do I submit receipts/documents to the job center digitally?

Hello dear community,

Is there any other way besides the standard benefits mailbox to submit a document requested by the JC? A specific one, such as a training certificate, a specific bank statement, or something similar. There's nothing for which there's a pre-printed online form. There's no suitable request among the messages you can send to the JC.

I recently received a letter stating that I still need to submit certain documents, even though they've been sitting in their mailbox for a month. Or do I have to submit the documents to the AfA later, even though the letter came from the JC? That would be the right request to choose from.

Thanks in advance.