Hello mariate,
Do you have Zoom enabled on your iPhone? If so, try disabling it with these steps: If your Home Screen icons are magnified on your iPhone, iPad, or iPod touch
If your Home screen icons are magnified on your iPhone, iPad, or iPod touch
If the icons on your Home screen appear too large or are magnified to fit the screen, your device may have the Zoom feature turned on. Learn how to turn off Zoom.
Turn off Zoom in Settings on your device

If you can't access Settings because your Home screen icons are magnified, double tap with three fingers on the display to zoom out.

To turn off Zoom, go to Settings > Accessibility > Zoom, then tap to turn Zoom off.
Disabling Zoom should solve this issue.
Let us know how it goes, take care.