I suppose this is a stupid question, but I can't find the answer in the user guide. I have 1Password on my Mac iPad and iPhone, synched through iCloud. But I can't figure out how to get the extremely strong and impossible to memorize passwords to fill in on Safari sites.
The Safari sites on the iPhone and iPad, to be clear. Works fine on the Mac.
Apple doesn't allow 1Password to pass information directly to Mobile Safari. You will either have to cut and paste your passwords into Safari or use the browser that is built in to 1Password (1Browser). The issue is Apple's rules, not 1Password's implementation.
If you do use 1Browser, you will get the automatic fill and submission that you are looking for.
I really hope that someday Apple relents on this kind of stuff!
Is it for the same reason that we cannot fill in the sign in requested login/password using the 1password data in third parties applications?
You're right, the same reason applies to 1Password filling in third party apps. We'd love to be able to do this, but until Apple's rules change, we cannot do anything in another app unless that app specifically allows us permission. There are, however, a growing lists of apps who have added 1Password support. Check out Apps that Love 1Password to see!