Once you have converted the WP Energy into Kafra Points, the points will be available for you to use on the Ymir, Valkyrie, or Yggdrasil servers.
You can view your current Kafra Points through the Kafra Shop NPC in-game or by clicking on
Power-Up at the top of this page. This page will also show you the current points on your other game accounts, along with the amount of WP Energy your WarpPortal account has remaining.
From this page, you can also check your WP Energy to Kafra Point transfer history. This can be done by clicking on the game account on the left, then clicking View Transaction History at the top of the page. The tab marked WP Energy Transfer History will show you the points that have been transferred.