Summary
The iPhone provides many different ways to customize its settings, but most settings fall into one of three categories. Fun and personal changes represent settings that have no effect on the performance of your iPhone, such as changing the wallpaper image.
Usability changes represent settings that can make your iPhone easier and more convenient to use, such as setting a Do Not Disturb schedule or increasing the text size to make text easier to read.
Potentially critical changes represent settings that could be important to your safety and the security of your data, such as setting up the Emergency SOS call feature or checking the privacy settings to make sure you aren't giving access to an app you no longer need.
Remember, you don't need to modify all the possible settings. The same procedure for turning on a particular setting can be used to turn off that same setting, so make sure you know the steps for turning a feature on or off just in case you need...