How do I change the height of my flat land so that I can finish my creation? I wish to make the area height 100 blocks. Now I'm trying to figure out how to copy and paste builds. Is that even a thing on here?

Try these commands:

If you're on your own map (e.g. 123DMWM_+2) then you should use /os map resize [width] [height] [length]

If you want to use that command for any map, use /resizelvl [map name] [width] [height] [length]

6 minutes ago, ikkebinz said:

Try these commands:

If you're on your own map (e.g. 123DMWM_+2) then you should use /os map resize [width] [height] [length]

If you want to use that command for any map, use /resizelvl [map name] [width] [height] [length]

They didn't allow me to build beyond 64 blocks high. What now?

We need more information. Is this singleplayer? is this multiplayer? What server is it?
What specifically happens when you try to use the commands you were provided?

Just now, Goodly said:

We need more information. Is this singleplayer? is this multiplayer? What server is it?
What specifically happens when you try to use the commands you were provided?

I'm on my singleplayer level. I'm doing some fnaf animatronic builds. I did them a while back and want to get back into it, but the level won't let me build any higher than 64 blocks high.

You can't resize levels in singleplayer.

But you can create levels with bigger volumes. If you're playing Enhanced, you can change the sizes to whatever you want, from 1 to about 16,000.