Samsung Note 4 Crashing Repeatedly
Go to Settings > About Device > Software Update and hit Update if any update is available, go for that.
If updating software can’t solve crashing then you need to conduct a factory reset.
For that go to Settings > Privacy > Factory data reset > or Settings > Backup and reset > Factory data reset.
FYI: don’t forget to backup your data.
After trying the above things if still the crashing problem is giving you trouble then it could be a hardware fault, so contact a technician.