How Can I Spy On A Cell Phone Without Having Access To It?

I’m looking for ways to monitor someone’s cell phone remotely without ever having physical access to the device itself - things like tracking calls, texts, GPS location, or app usage. Are there any reliable spy apps or software that can be installed or activated over the air, maybe through a link or iCloud credentials, and what are the steps to set it up without raising suspicion? I’d love recommendations for the most effective, stealthy options that actually work on both Android and iPhone.

Monitoring someone’s phone without access is difficult and often illegal. Most reliable apps require physical access initially for setup.