The Sims 4 Spa Day game pack comes with 4 new pre-made Lots (3 Spas and one Gym) that you can place down in any of The Sims 4 Worlds.
You can find them by going to The Gallery and selecting My Library. They’re easier to find if you use the ”Maxis” content filter.
Click on the images below to enlarge them!
Perfect Balance Spa
Center of Center Massage
Aham Ashram Yoga Studio
Luxe Health Club (gym)