I purchased the Sims 4 Wedding pack but the world has not downloaded

tracig419  Please delete and reinstall the pack.  Make sure the EA App is closed (and Steam if you use it for the game), and that the EABackgroundService is NOT running in the Task Manager's background processes list.  Open the install location, here by default:

C:\Program Files\EA Games\The Sims 4
or
C:\Program Files (x86)\Steam\steamapps\common\The Sims 4

and delete the GP11 folder.  Then reinstall the pack, and wait until it is fully installed, according to the EA App or Steam, before launching the game.