Kicad - Custom library folder
To create a new library:

Click on the "Create New Library" button on the top left - 



To choose a library for your new symbol:

When you click the "New Symbol" button it prompts you to choose which library you want to add it to. Click on the library you want and press "OK" (or just double click).



Then just save your symbol as you normally would. It'll be added to the library.

To move a symbol to a different library:

It's as simple as Cut &amp; Paste.




To export the symbol you're currently viewing into a different library:

Click the "Export" button...



... and save it to the library you want.