What is the ruling on working from home by filling out forms or inviting people, for a fee that increases with the number of messages sent?

The basic ruling regarding writing forms for companies and sending messages in exchange for financial compensation is permissibility. This is because it falls under the category of ijarah (leasing/hiring), which is originally permissible, in accordance with the Almighty's saying: "Allah has permitted trade and forbidden usury" (Al-Baqarah: 276). However, if these forms or messages include promotion for something unlawful, such as riba (usury) or prohibited transactions, then writing or sending them is not permissible. This is because it constitutes cooperation in sin and aggression, and due to the Almighty's saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression. And fear Allah; indeed, Allah is severe in penalty" (Al-Ma'idah: 2).