In The Sims Mobile you can collect heirlooms. These collectibles unlock new features and new careers for your Sims. You can earn these souvenirs by sending your Sims for retirement. You can also buy them at the heirloom store.
Since June you can buy heirloom chests in The Sims Mobile. Depending on the quality of the heirloom, the box costs 25 heirloom vouchers, heirloom Supervouchers or heirloom Megavouchers. You can also open a Family Chest every 48 hours. It will get you a few different heirloom vouchers.