Signal was one of the choices I saw in my search, but I have no way of judging whether it’s good or bad. Can you help, please?
Its neither good nor bad. Its a messaging app that encrypts. The message can only be read by the sender and the receiver. (Who knows if NSA can crack it or not). The only way for someone to see the conversation is if they get your device or the recipients device and the messages have not been deleted afterwards.