Sending SMS text messages from an iPad isn't as straightforward as you might think.
You'll have noticed the pre-installed Messages app, but that's for sending iMessages (which can only be sent to other people on an iPhone or iPad) rather than conventional SMS text messages (which you can send to anyone with a phone). In this article we outline the other options that let you send texts from an iPad.
The Messages app on an iPad is limited, because it can only send iMessages. These are better than SMS messages (because they're completely free) but also worse (because you can only send them to other people on iMessage - which is to say, other iPad, iPhone and iPod touch users).
Start up the Messages app and tap on the compose button - it's the square with a pencil piercing it diagonally (to the right of the 'Messages' heading on the lefthand bar in the picture below). Start typing the name of the contact you want to send a message to, and iOS will offer to complete it for you.
But can you send a message to that person? If the name is blue in the auto-suggest field, they're on iMessage and you can send them a message without paying a penny. If the name is grey - and then displays as red when you select it - they are not (they're probably on Android) and you'll find that you get a 'Not Delivered' error message, or won't be able to activate the send button at all.
Text messaging apps
There are other options, however. Search the App Store for texting apps, and you'll find plenty of free offerings.
One we find pretty usable is TextMe, which offers a small number of SMS messages for free, generating a phone number that your message will appear to come from (so remember to sign off with your name, or the recipient will think they are being stalked).
Once the initial credits are used up, you can get more by watching video adverts or by inviting friends - or by paying, of course. And the game itself has a fair few ads, even appearing amongst the messages in the conversation window. (These too can be removed by paying.) But it's a solid enough app if you're in urgent need.
Of course, if you've got web access via Wi-Fi or cellular, it's worth questioning why you need to specifically send a text from your iPad.
The most obvious free alternative is email, although most people are less likely to notice emails than texts. Try sending a tweet instead, which while limited on characters does allow you to attach images. The average Twitter user will have notifications set up so they're immediately alerted to direct messages or mentions.
Personally I find that within work hours the best option is often Slack; either a direct message or a public message mentioning the person's username will generate a notification. Many people have do not disturb set up out of office hours, however, so it's less useful then.
Read about how to hide text messages on an iPhone here.