How to create an End Portal in MineCraft?

12 eyes of Ender are needed for this. Put down portal frames, 3 on each side and place an eye of Ender in each one and it should work. ^__^

To make a portal take the frame and put 3 down, on the CORNER end of it put 3 down in a line, do the same until it makes a square-circle shape, and put the eyes in on the holes in the frame bits, and it should work, if not watch this video.

I'm assuming you're playing vanilla Minecraft.

There's no way to legitimately construct an End Portal in survival mode.

Using the /give command, you can spawn in End Portal blocks and the actual portal block itself. To do this, you can use the following commands:

/give @p minecraft: end_portal 1
/give @p minecraft: end_portal_frame 1

This will give you the End Portal and the End Portal Frame. You won't need to activate the portal in the normal way (12 Eyes of Ender) because the portal will already be there. The End Portal Frame will just be for aesthetics. You can change this around if you want.

You can't make the End Portal, you can only find and activate it.

Unless something has changed that I'm not aware of, Creative Mode made End Portals do not work and you can't make the blocks in Survival Mode at all.