Nope, it’s not, but finding a good potting mix isn’t hard. Good potting soil has a light crumbly texture and retains moisture without becoming muddy or swampy when you water it. The best choices for most houseplants should have lots of organic material (humus, compost, bark, loam) and some peat moss. Organic brands are great options.

Lots of times you see recommendations for soilless mixtures that don’t contain any organic material because they have good drainage and don’t compact. These are made mostly from peat moss mixed with vermiculite, a mica, or perlite, a type of volcanic glass. But they also don’t have any nutrients, aside from whatever the manufacturer adds in, and they dry out more quickly. A good organic humus  mix will serve you better in the long run.

An environmental note about peat moss: 
Peat moss, or sphagnum peat moss, is a common ingredient in potting mixes. Peat moss is mined from bogs, mostly in Canada and Europe. It’s formed as moss decomposes over several millennia beneath the bog’s surface without the presence of air. It’s great at retaining water while still providing good drainage, which is why it’s become a popular ingredient in potting mixes. Unfortunately, it’s also a nonrenewable resource since it forms so slowly, and mining it releases a lot of carbon into the atmosphere, so it’s best to look for mixes that use it sparingly. If you’re interested in learning more, you can read this deep dive into the peat issue in the Washington Post.

Specialty soil mixes: 
Most houseplants will love an all-purpose, ordinary organic potting mix, but some are a little extra. Cacti and succulents like a sandy mix designed especially for them (although most will deal if you don’t want to buy them something separate). Orchid mix contains a lot of bark and hardwood charcoal, which works for orchids and other epiphytic types like bromeliads that naturally grow clinging to trees or logs rather than in the ground. The blend is named for orchids because they are especially fussy about it.