In The Sims 3: Generations for the PC, typically you can’t edit any Sims once you’ve saved their settings and added them to the game to play. There are some cheats however that make this possible, even allowing you to edit Sims that aren’t in your household.
To edit a Sim in your current household, hold Ctrl + Shift and hit the C button to bring up the command prompt. Type in moviemakercheatsenabled true and hit Enter. Now hold Shift and left click on any Sim in your household. You should now see the option to Edit in CAS, which will bring up that Sim in the Create-A-Sim editor.
To edit a Sim that isn’t in your household, you can just select that household and edit them the way I specified above, or you can add them to your household and then edit them, after which you can move them back to the other household. Hold Ctrl + Shift and hit the C button to bring up the command prompt and type in testingcheatsenabled true and hit Enter. With this option enabled you can hold the Shift key and left click on any Sim to add them to your current household. Once they’re in your household, use the method listed above to edit them.
