build mode not working

@shaila68  Please clear Origin's cache:

https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/

and repair the game: open your Origin game library, right-click on the Sims 4 icon, and select Repair.

If that doesn't help, please test in a clean user folder.  Move your entire Sims 4 folder out of Documents\Electronic Arts and onto your desktop, and when you launch the game, a clean folder will spawn with no content.  Don't add anything to it yet; just open a new save and have a look at Build/Buy.

If everything looks normal, you can copy the contents of your saves and Tray folders from the old Sims 4 folder to the new one and pick up where you left off.

@puzzlezaddict when i moved my sims 4 folder, the build menu still didn't show up

@shaila68  On the off chance that you use OneDrive and it's syncing the contents of Documents, please make sure that you don't have any of your previous content in the game.  As in, when you load Sims 4 after moving the user folder, you don't have access to your saves or anything else.  If you do in fact see your saves, please let me know.

Otherwise, if clearing Origin's cache and repairing also doesn't or didn't help, then you might need to do a full reinstall of Sims 4, unfortunately.  All your saves and other user content will be intact in the Sims 4 folder you've moved, so you don't need to worry about that.  And you'll be able to download all your packs again.