You normally can’t — most websites don’t allow to see the code multiple times. You generally would have to creat a new code for the site, which usually requires a painful procedure to reset the old one.
But your FreeOTP backup should be in iCloud or iTunes backups (however I am not sure how good that works.
I know it’s too late now,but for thefuture: I typically don’t depend on it and copy all secret keys in addition to a offline password manager, by clicking the „show qr as key“ links. This may of course weaken the factor, if not handled carefully.
Gruss
Bernd
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http://bernd.eckenfels.net