While PC classes are the exception to magic users, various types of ritual magic are quite ubiquitous in my world to the extent that people don't even know they're doing magic. So the blacksmith hums a tune and follows a pattern handed down to him while making a knife and the knife never rusts and stays sharp longer than it should. The baker's cookies really are magically delicious and their bread stays fresh longer. People can go to the local herbalist and get effective medicine so, for example, childhood mortality is dramatically reduced. Most homes have at least one source of magical light because even though it's expensive having a 100% safe light that lasts literally forever is game changing.
But it goes beyond that. People heal faster because their bodies take advantage of magic. So that broken leg that would normally heal in 6 months instead takes 6 weeks. People don't realize they heal faster because to them, it's just normal. I still use gritty rest rules because, along with reasons of pacing, because it still takes time to recuperate. It's just much faster. Other supernatural things are, if not common, not particularly surprising. Innocuous house spirits are relatively common, that piece of equipment that's particularly stubborn may indeed be inhabited by an elemental.
But it also explains stagnation of technology and some of the oddities of D&D. Gold is more common because some alchemists really did learn to turn lead into gold, but there's still a cost to the transformation. Technology has stagnated in some ways, why create a steam engine when you can create a golem that, again, will last forever with minimal maintenance barring accident. Meanwhile those steam engines need special protection lest steam mephits decide it would be a fun "home". Crops grow faster and are harvested slightly more effectively, getting close to crop yields we see with modern fertilizer.
On the other hand, I don't go to Eberron levels of magi-tech. There are no magical railroads, while there is the occasional flying ship they're rare. The wealthiest people might have a carriage pulled by magical horses if they want ostentatious displays of wealth but even for the wealthy it's rare.
Magic is pretty ubiquitous in my campaign world, but it's mostly in small ways that serve to aid people in their everyday lives.