How to allow your iPhone or iPad to store Usernames and Passwords in Safari.
1, Open up the ‘Settings’ app on your device, scroll down and click on ‘Safari’
2, Click ‘Passwords & AutoFill’
3, Next to ‘Names and Passwords’ toggle the slider to show that it is enabled
4, If you encounter this screen then you may wish to insert a passcode to your phone by clicking ‘Turn On Passcode Lock’ and following the instructions.