How can I find location history on my iPhone?

Settings>>Privacy&Security>>Location Services>>scroll down to System Services>>Significant Locations.

FelipeV gave you the only place you can check, but be advised, your phone does NOT store all the locations you've visited. It stores significant locations, which are typically home and work. It would be a privacy issue for the phone to show everywhere you've been with your iPhone.

Even if you go to the settings FelipeV recommended, you can't see the entire history, only recent records.

The iPhone doesn't offer any way to do what you want.

If you have a Google account on your phone and you've configured it to save your location history, you may be able to find it there.

https://support.google.com/maps/answer/6258979?hl=en&co=GENIE.Platform%3DiOS&oco=0

You may also have other third-party apps on your phone that safe location history.

As stated, your iPhone will only keep track of places you have recently been, as well as how often and when you visit them, in order to build a list of your Significant Locations. Those are used for personalized features such as Predictive Traffic Routing, Siri, App, Focus suggestions. This does not show all the locations you have been to, as your iPhone is not intended to be a 24/7 tracking device. That can be seen as a major privacy violation. While there are third-party apps you can download from the App Store that will track your location 24/7, those take up a lot of battery as they are constantly updating your location.

Apple removed the ability to view your previous Significant Locations years ago due to privacy concerns as your phone is not intended to be a personal tracking device.