After sychronizing, will all my userids and passwords be synchronzed?

After sychronizing, will all my userids and passwords be synchronzed from my iMac to iPhone?

I am not sure, and is that a great idea.

For example if you update or loose it on one it could imply you may loose it on all.

Hi,

To answer your question, you can choose whether to sync logins (and other data). Please see Sync bookmarks, logins and browsing history on Firefox for iOS.