There are a few different ways that you can put a background on your text messages. One way is to use an app that will allow you to do so. There are many different apps available, so you will need to find one that suits your needs. Another way is to use a website that offers this service. Once again, there are many different websites available, so you will need to find one that suits your needs. The last way is to manually add a background to your text messages. This can be done by using an image editing program such as Photoshop or GIMP.