The WhatsApp application is widespread all over our planet and others (to call other planets, however, you must pay a subscription). Thanks to this wonderful application, you have the possibility to send voice messages, photos and even videos. You can use WhatsApp on Nokia S40, Android, Windows Phone, BlackBerry, and Symbian device.
Steps
Part 1 of 2: Create your account

Step 1. Create a user account
First of all, launch the WhatsApp application. Once on the "Your phone number" screen, enter your phone number then press the OK button (done).
- You must then select the country in which you live. Tap the country name and select your country from the list.
- When you create a user account, the WhatsApp application will send you an SMS message containing a verification code. To continue, you will have to enter this code. If you cannot receive an SMS, you have the option of receiving an automated phone call.

Step 2. Write your name
When you are on your user profile page, enter the name you wish to use and then press the OK button (done).
- You can write any name you want, your real name or a pseudonym.
- It is possible to add a nice photo to your profile to personalize it.

Step 3. Find friends
WhatsApp will now ask you if it can access your phone contact list. If you agree, the WhatsApp application will perform a search to determine which contacts are using WhatsApp to add them to your favorites. You will then have all your contacts in your WhatsApp contacts page.
In case you don't want the WhatsApp app to access your phone contact list, you will be able to add contacts manually in the future
Part 2 of 2: Send a free SMS

Step 1. Go to your favorites
Select the "Favorites" option.
It is also possible to send messages from the chat screen

Step 2. Select a contact
Tap the name of one of your contacts.
In case none of your friends are using the WhatsApp application, you will need to send them a personal message and ask them to install WhatsApp on their mobile device

Step 3. Write your message
Write a message and then press the "Send" button. You will be able to see the message appear above the chat text box.