Gmail
Your Google account is probably the one you want to secure first. Not only is your email account a repository of all sorts of important information, but also, since our email ids are the default way to sign into Web services today, your Gmail account can also serve as a gateway to all your other accounts. To set up two-factor authentication, you need to take the following steps:
1. Go to Google Account Security and under Password, look for 2-step Verification.
2. Click setup. On the next page, click Start Set Up.
3. At the next page, sign in. In the box, enter your phone number.
4. Choose the mode by which you will receive the code > click Send code.
5. A six-digit code will arrive on your phone via text message or by a call. Enter the code on the website and click Verify > Next > Confirm.
6.Next, Google will ask you to reconnect all your apps and devices. If you've configured apps to access your Google account on any device, you will have to create a separate app password for each and sign in again.
To do this, click Configure when Google prompts you to. Now select the app (click Other if it isn't mentioned) and device from drop-down menus and click Generate. Each code password you generate will only work for one app.
Facebook's two-step verification is not available in all regions as of now. If it is available in your region, here's how to set it up.
1. Open Facebook account security settings. If you see a header called Login Approvals, under Login Notifications, then this is available in your region. If not, then you'll have to wait till Facebook rolls out this feature.
2. Click the Edit button next to Login Approvals. Check "Require a security code to access my account from other browsers". Click Save Changes. Click Get Started in the pop-up.
3. Now you'll see a pop-up titled Alternate Security Code Delivery. Click Continue, re-enter your password and hit Submit. Finally, you can key in your phone number and click Continue. Now you will be sent a code via text message. Enter this code on the website and hit Confirm.
4. Facebook will now tell you that you can disable Login Approvals within a week. In case you don't, you will need the security code sent via text message every time you log in from a new browser. Facebook also lets you a few login approval codes that you can use when you don't have your phone. You may use these while you are travelling and your phone is out of coverage area.