If you'd like to change the default password other devices use to connect to your Mobile Hotspot, check out the steps below.
From a Home screen, navigate: Apps icon > Settings .
Tap Mobile Hotspot and Tethering.
Tap Portable Hotspot.
If prompted, review the info then tap OK.
From the PASSWORD field, enter the desired password.
If the field is greyed out, tap the switch (upper-right) to turn off .
Password must be at least 8 characters, see example image below.
Tap Show password to view the entered password.
Tap the left arrow icon (upper-left) to save and return to the previous screen.
The new password must be entered on the connecting device.
Check out these FAQs for additional support on Mobile Hotspot or if you're prompted to add it.