You can make use of the action flows to send WhatsApp text messages to your contact from your app. In that case, you can make use of the WhatsApp Message action under Action Flows > Utility block to carry out the task.
Message text: is the mandatory field to send a WhatsApp message. You can also make use of the Keywords to use text from your apps like messages inserted from apps or notifications sent from your apps.
Phone number: Is the mandatory field to add the receiver’s phone number. The phone number should be entered in a valid format as (country code )+(phone number).
Enter the message text and phone number. Each has an option to add keywords. Thus you can make use of the input controls and other input values to complete the action to send WhatsApp text messages.
Now, whenever you click the Action button your action flow would be triggered and the specified text message would be sent.
In the example below, we will be sending the message that is entered in the Text control and accept the phone number using the phone number. You would need to use a Compute block that uses the Concatenate() function to get the phone number in a valid format. Now when you click the “Send Message” button, the action flow is triggered.
Then configure the WhatsApp Message block where you simply need to assign the message text and phone number. In this example, we are adding the respective keywords namely the text control and the output of the Compute block.
Whenever you run the App in preview it will open the Configure WhatsApp web on your system. Once you Publish the app and run it on your mobile devices, whenever you click Send Message button it opens the WhatsApp on your device and goes to the message box to the contact from your list whose number you have entered. The Message is already added in the message box and you just need to press Send and your message is sent to the selected contact.