The ESV and NIV aren’t stored in this app. They belong to their publishers, who lend them out one passage at a time. To borrow them you need a key of your own.
A key is just a long password the publisher gives you. It is free, it takes about three minutes, and it asks for nothing but an email address. It doesn’t cost anything and there is no card to enter. The key only tells the publisher who is asking.
Below there is one box per translation. Get the key, paste it in the box, and that translation joins the menu at the top of the screen. Nothing else changes.
Nothing to do. Tyndale lends the NLT to anyone who asks, so it is in the menu already. Choose NLT at the top of the screen and it appears.
Your keys stay here. They are saved in this browser only, and never sent anywhere but to the publisher they belong to. The one way out is the export file under data, which carries them so you can set up a second browser of your own. That is also why the file is yours to keep rather than to pass on. It can be exported without them.