Hey there ThisisClara,
Thanks for reaching out to the Apple Support Communities. To get started, can you let us know some more details about where you're seeing this cut off on the display? For example, is this occurring on the Home Screen, or any a particular app?
Since noticing the issue, have you tried restarting your iPhone? If not, give that a try with the steps shown below: Restart your iPhone - Apple Support
How to restart your iPhone X, 11, 12, 13, or later
1. Press and hold either volume button and the side button until the power-off slider appears.
2. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
3. To turn your device back on, press and hold the side button (on the right side of your iPhone) until you see the Apple logo.
While restarting may seem like a simple step, it can often help with resolving some unexpected issues like this.
Also, do you by chance use the Zoom feature on your iPhone? More details on this feature here: Zoom in on the iPhone screen - Apple Support
Let us know what you find, and we'll continue from there.
Take care!