If you want to download Packs, make sure to check that your computer meets the additional requirements. These are the requirements for The Sims 4 base game, no Packs included.
If you want to keep playing the game while running macOS Lion, don't update The Sims 4 to any future game patches. We no longer support The Sims 4 on the macOS Lion (10.7) operating system. Check here to find out if your PC or Mac can run The Sims 4 and The Sims 4 Expansion Packs.