How to enable iCloud password for all sites on iPhone and iPad: ICloud keychain is great. But some sites block the saving of passwords. Fortunately there is a way to force iCloud to remember password for all sites on iPhone and iPad, regardless if they want you to remember the password or not!

goto settings > safari > passwords and autofill
toggle the switch for ‘Names and Passwords’ to ‘on’
then toggle the ‘Always Allow’ switch to ‘on’ too.