cannot get alerts when text messages come in i phone 6
Welcome to iMore! Go to Settings > Notifications > Messages, and make sure that you have alerts enabled for the messages app. Also make sure that you don't have Do Not Disturb turned on by sliding upward from the bottom edge of the screen to open the control center. The button with the moon icon should be shaded dark to indicate DND is off and you should not see a moon icon at the top right of your screen near your battery indicator.
If you're still experiencing issues reset your device by holding the power button and home button down simulatneously until you see the Apple boot logo.