Creative

#How do I get a plot?

With /plot auto. More under Plots.

#How do I let friends build with me?

With /plot add <player> while you are online, or /plot trust <player> even while you are offline.

#May I use WorldEdit?

Yes, on your own plot. More under WorldEdit.

#Can I download my plot or save it as a schematic?

No.

#Are there monsters or PvP?

No. It is always noon and there is no weather. With flags you set time and weather for your plot.

#May I use Litematica?

Yes, Litematica is allowed in Creative.