Getting started

Open or create the collection you want the cards to land in.
Tap Scan. The browser asks for camera permission the first time, and that permission is between you and your browser: the video never leaves your device.
Hold the card so the name is readable. It does not need to fill the frame or be square on, and the name can be anywhere in the picture.
Cards go into a queue rather than straight into your collection, so you can look over a stack before committing it.

Scanning a stack quickly

Keep the phone still and move the cards, rather than the other way round. It focuses faster.
Any flat, evenly lit surface beats holding a card up to a window. Glare on a sleeve is the single most common reason a scan fails.
The queue shows what it read, so you can scan a pile and check the whole lot at the end rather than watching each one.

When it gets one wrong

The scanner reads the name correctly about 97.6% of the time, which still means roughly one card in forty needs a hand. Two different things can go wrong, and they are worth telling apart:

The wrong card. Rare, and usually a name it could not read at all. Remove it from the queue and type the name in.
The right card, the wrong printing. Much more common, because most cards have been printed many times and the art is not what is being read. The queue marks scanned rows differently from typed ones for exactly this reason: a typed card is the card you meant, a scanned one may be the right card from the wrong set.

If the printing matters to you, check the set and collector number on the queued row before you add it. If it does not, add it and move on.

Cards that need a little help

Sleeved cards. A matte sleeve is usually fine. A glossy one throws the light straight back at the lens, so angle the card slightly rather than turning up the brightness.
Foils. The same problem, more so. Tilt until the rainbow moves off the title bar; the name is the only part being read, so the rest of the card can stay shiny.
Double faced cards. Scan the front. Wizbook files transforming cards under the front face, so a card scanned from its back will not be found even though Wizbook has it.
Cards in another language. Wizbook's card data is English only, so a Japanese printing will not match by name. Add it by its English name and the printing details can be set afterwards.
Old cards with ornate frames. Pre eighth edition type is harder to read than modern type. If a card refuses twice, it is faster to type it than to keep trying.

Where the cards end up

Scanned cards join the same queue typed ones do, so you can review the whole pile before anything is added.
From the queue they can go into your collection, or straight into a deck, a binder or a wishlist, without a round trip through the collection first.
If you have no collection open, Wizbook asks you to make one first rather than quietly holding cards with nowhere to put them.
Nothing is written until you add it, so a queue you abandon costs you nothing.

What leaves your device

The camera feed does not leave your phone.
Reading the name may send the cropped area around the card name to an OCR service, and nothing else: not the picture of the card, not anything about you or your collection.
Everything else about the scan happens on your device.

The About page lists every outbound request Wizbook makes, in full.

If you would rather type

The Rapid Card Adder takes names as fast as you can type them, with autocomplete, and drops into the same queue. Scanning and typing are two ways into one place, so you can mix them freely on the same pile.

Scanning cards with your phone