Mailing bot

Hello! I'm a bot developer on your platform. I got a request to make "mailing" bot on a server, so bot texts to members in DMs, notifying about any news or whatever. We know about your relation to the spam-bots, and that's why I'm currently contacting you. Here is the question: is it fine if we make the bot to send messages only to the users who agreed with our terms about the "mailing"? If it's, how'd be better to fix the agreements? Imagine an interaction / reaction, either text agreement, the user may delete the message / remove the reaction. Does your database save message or interaction ids, so we can prove that the user actually agreed with our terms? With best regards, Hayer