Send it through teamspeak, once the roleplay situation has started, tell the officers on scene if they require any kind of documentation you can provide it, if so send the link to one of them
Hey Steve, the usual method is during your RP with the police, is to mention you have the document, and send it over through teamspeak to the relevant officer, of course if your RP requires that you need to send the document prior to commencing the work, then the same applies.