It's easy to send text messages using Siri. Ask Siri to "text John Smith" and you'll be asked to speak the message and then confirm that you want to send it.
Sometimes, however, dictated messages don't come out right and it's important to know how to send messages using the Messages app if you want to ensure a message is written without errors.
Start the Messages app by locating the app and then double tapping or instruct Siri to "launch messages".
If you hear "back, button" then double tap to return to the main messages page. To start a new conversation, the messages compose button is near top right of the messages screen. You should be able to locate it either by sliding a finger near top right or by swiping a few times to the right.
Now double tap to compose a new message.
You should hear "Too, text field, is editing". There are several options here to enter the names or numbers of the people you wish to text.
To keep this page simple, I will describe only one method here.
Swipe right and you should hear "add contact, button". Double tap and you should hear "contacts, heading". Swipe right until you hear "section index, adjustable". The section index is like the alphabetical tabs on a paper address book and you move from tab to tab by swiping down or up. Now swipe down until you reach the first letter of the name you're looking for. Depending on a setting, you'll be indexing through either the first or last names of your contacts. Let's assume that the setting is set for last name and you are looking for John Smith. Swipe down until you reach the letter S and then swipe right to go through all the contacts whose last name begins with S until you reach John Smith. You may hear a few names beginning with the previous letter, R in this example, before you start hearing the names beginning with S. When you have found the correct contact double tap to select that contact and display that contact's information. Swipe right until you hear the mobile number announced and then double tap to select it.
Now swipe right until you hear "message, text field". You can now either dictate, handwrite or type the message.
Finally, you need to locate the Send button. You should be able to do this with a single swipe to the right. Double tap. That's it; the message is sent.