Ah, Herobrine. For years you have eluded the most determined of Minecraft fans. Existing just on the edge of possibility in a part of the world nobody could seem to find. But it turned out there was a reason nobody could find where Herobrine lived, it’s because he doesn’t exist, not officially anyway.
There is no way to spawn this elusive NPC in the game legitimately. You can build all of the portals you want, sacrifice as many cows as you desire, he will not appear.
The only way you can definitely spawn Herobrine in your game of Minecraft is to use mods. You can have him join you, or just do things around your home. Whatever you can find a mod for. But without the power of mods you will never get to share a screen with the legend that is Herobrine.