Use the Right Charger
Unfortunately, your iPhone no longer comes with a charger. But to be fair, even when it did, it wasn’t a fast charger.
Instead, you need to get a charger that supports fast charging. A 20W charger from Apple will do the trick. Recent iPhone Pro models can change at faster speeds, and there’s no harm in using a higher-wattage USB-C adapter if you have one around. However, it won’t speed things up as much as you might think, so sticking with the standard 20W adapter is fine — and it’s also healthier for your battery in the long run.