What is the ruling on working monthly in a forum by transferring topics from other websites and answering members' inquiries? And is it necessary to mention the original source and author of the transferred topics, or is it sufficient to just say "transferred" when the source is unavailable?

Working in forums is permissible, whether paid or unpaid, as long as the topics do not include a Sharia-prohibited matter. The source and author must be mentioned as an academic integrity. It is sufficient to indicate the transferred material with "transferred" or similar if the source is unknown. Also, one must be careful not to publish unconfirmed information.