I would type traits.equip_trait bookworm to get the Bookworm Trait. Always backup saves before doing a lot of cheating. Doing this lets you remove them, though sometimes modifying traits can cause issues. Create-a-Sim Personality and Bonus Traits Personality-style traits can be equipped like this, but you're also able to go into Create-a-Sim with the cas.fulleditmode cheat (use testingcheats on first). Note that if you have trouble getting one to work you can attempt to put trait_ before it, such as traits.equip_trait trait_DogLover. Use traits.equip_trait TraitName to add a trait to your Sim, or traits.remove_trait TraitName to remove them. Once the console (a white box in the upper left corner) is open, you can now type in commands. Playstation and Xbox players can do this by pressing all four shoulder buttons simultaneously. Do it all in one fluid motion with your keyboard. In order to cheat traits, you must first bring up the console by pressing Control + Shift + C. You can equip and remove traits very easily. How to Cheat The cheats console is visible.

Although you probably found this page there, my site does feature an extensive list of Cheats in The Sims 4 if you would like to learn more. Here is a list of all traits in The Sims 4 and the codes you need to equip them. Traits often provide bonuses or penalties of some sort, and it may be desirable to remove them. The Sims 4 features many Traits beyond those found in Create-a-Sim. The Sims 4 Trait Cheats Personality and Reward Trait Codes Trait Cheats can let you equip dozens of abilities to your Sims, increasing skill gains and unlocking unique behaviors.

Sims 4 traits and goals list