Sweeping funds from a private key allows you to quickly and easily move funds stored on a paper wallet to a wallet in your Blockstream App.
Note: Instead of sweeping funds from a private key into an existing wallet, you can also import an outside wallet via its associated BIP 39 passphrase. Importing is the correct option if you're more interested in simply adding the wallet to your Blockstream App rather than moving the funds into an existing wallet via an on-chain transaction.
How to sweep funds from a private key into Blockstream App
1. Start by moving from the Home tab to the Transact tab via the navigation bar at the bottom of the screen. Then, click the Receive button on the Transact tab.
2. Once you're on the Receive screen, tap the icon with the three dots in the top-right corner of the screen. This will bring up a small menu at the bottom of the screen where you can select Sweep From Paper Wallet.
3. On the next screen, you will be asked to enter the private key you wish to use to sweep funds into your Blockstream App wallet. Alternatively, you can scan a QR code of the private key with your camera. Once the private key has been entered into the text box, you can tap the Next button at the bottom of the screen.
4. From this point forward, the process will look like you're making a traditional Bitcoin transaction. You will be able to select the amount you'd like to sweep from the private key and optionally set a fee for the transaction by tapping the Change Speed hyperlink. Click Next once you have set these parameters.
5. Finally, you will be given one last look at the transaction details and confirm them before it is broadcast to the Bitcoin network. If everything looks good, you can slide the arrow at the bottom of the screen to send the transaction. You will then receive a message that the transaction was successfully sent.