MacBook display has vertical black and white lines on startup
It's definitely hardware.  It's either the display has gone bad or your GPU (logic board) has gone bad (most likely case)

The first thing I would do is hook it up to an external monitor.  If it's present there as well, then you know it's GPU/logic board related.   If it goes away, then run Apple Hardware Test (AHT) to get some details.  (Hold the D key while booting from a powered off state with the AC adapter connected)

Either way, you will need to take it in for service.