Tom Clancy's The Division

Phone recordings are by far the most numerous collectible in the game, and they're littered everywhere. You can find them on rooftops, alleyways, sewer systems, trash cans, abandoned cars, and other various places. When you're near a phone, you'll hear a ringtone like someone is calling the phone. Simply approach the phone and hold to pick it up. Once you've collected it, you'll hear a recording related to life before or just after the virus outbreak. The picture below is an example of what a phone looks like in-game.

In order to make collectibles appear on the map, you have to activate the Security Wing of the Base of Operations and use the console to purchase the "Canine Unit" upgrade for 200 security supplies. Security supplies are earned by completing encounters and missions with the blue shield icon on your map. Once the Canine Unit is purchased, simply clear all side missions and encounters from a named zone to make Intel appear on the map. Note that some Intel items will not appear on the map due to their vicinity to other icons when zoomed out. In order to make them appear, push on your controller and push twice, to filter your map to only display Intel.

If you want view the phones you've collected, push the button on your controller, select Intel in your menu, push , and select Phone Recordings. The trophy will unlock when you collect the final phone.