You can play offline afterward, but will have to be connected in order to start the game for the first time. Please Note that The Sims 4 requires an internet connection for initial activation.
Here are the minimum and recommended requirements for running The Sims 4. The Sims 4 does not require a particularly powerful machine, but some of the requirements may be beyond a budget PC or laptop's abilities. The Sims 4 Requirements Can My PC Play it? & Shader Model 3.0 Help
