How can i see who someone is texting?

There is no honest way to see who an adult is texting without access to their phone or their account. For a child's Android device that you administer, a monitoring app installed with their knowledge shows the SMS threads and contact names; for iPhone there is nothing equivalent, which is why so many people end up disappointed by iPhone "text spy" apps.

What exists, by situation:

• Your child's Android phone — a monitoring app reads SMS/MMS threads, contact names and timestamps. This is the only case where "who are they texting" is answerable as a technical question.
• Your child's iPhone — Screen Time's Communication Limits control who can be contacted during downtime; they do not reveal who was contacted. Family Sharing gives location and purchases, not messages.
• A shared Apple ID — messages sync to every device on the account, so you see them because you are the same account, not because you spied.
• An adult partner or employee — without consent this is unauthorised access in most jurisdictions, and the phone bill only shows numbers and times, not names or content.

What does not work: entering a phone number into a website, "text message tracker" apps that ask for the number only, and anything promising to read another person's SMS from your own phone.

Where our app fits. Ultimate Phone Spy runs on Android 4.0+, Windows and macOS (features) and shows SMS, MMS and call logs for a monitored Android device. It requires installation on that device and the consent of the person using it.