You might want to back up your wallet for several reasons:
1. To transfer a wallet from one device/browser to another
2. To avoid losing your wallet when you clear cookies on your browser
To back up your wallet, you simply have to copy and save your secret ID/private key. Please follow the steps below to backup your secret ID/private key.
1. Click the blue circle on the bottom right corner of the page.
2. Choose "manage wallet"
3. Click "export wallet"
4. You can find your secret ID/private key which is made of small and capital letters right above the QR code. Make sure you save it securely (copy and paste it into a text document) or write it down for future use.