Any planet you discover on your journey is marked on your galactic map, along with its name, its atmosphere and what resources you found there. If you choose to, you can then share that information with every other player, uploading it so that its shared across everyones galactic map.
Youll get credit for discovering it. Youll also, if the materials there are valuable, attract players to come visit. No Mans Sky isnt a multiplayer game, in as much as youll never see another player. But the galaxy is the same between everyone and actions of significance will be shared. If you kill a single bird, that wont be shared. If you make an entire species of bird extinct, then those creatures will blink out of existence for everyone.
That means you might want to keep quiet about a planet of valuable resources, so others dont come and deplete it.