Q: Why does my iphone have black and white lines at the bottom of the screen?

Good Afternoon Millierosexxx,

Here's what to do if you are seeing lines on your iPhone display:

Get help with the screen on your iPhone, iPad, or iPod touch - Apple Support
http://support.apple.com/en-us/HT203039

If you see lines, missing sections, discoloration, or poor image quality

1. Try to restart your device. If you can't restart, reset your device.
2. If restarting or resetting doesn’t fix the issue, restore your device.
3. If you still see the issue after you restore, contact Apple Support.

If this turns out to be a hardware issue, after a physical inspection of your iPhone, the repair options will be explained to you.  

Regards,

- Judy