Pastebin.com is the number one paste tool since 2002. Pastebin is a website where you can store text online for a set period of time.
Roblox's equivalent of prefabs or templates is in the works but not really there yet. In the meantime, the best way to get the equivalent is to do it yourself: create the thing you want to use as a template, keep it either somewhere out-of-the-way in Workspace or hide it in Server...