The easiest way to make your own silicone wristbands is to get customized ones ordered from manufacturers. There are online shops which will allow you to customize wristbands based on your chosen colours, sizes, written words, and patterns, etc. For those busy people who have no time for such self-made products, all of that is in your control except for the actual creation of the product.
But if you want full control from the very beginning, the best option is to make them at home. In order to do this, you need to prepare a batch of blank silicone wristbands in any colour and a screen printing machine or an embossing machine. In fact, these two machines will make a wristband look very differently, so you should pick the one that best accents the design you have in mind. But regarding the result, both machines work well with other materials. After having picked your phrase or word, you need to place the wristband in the machine, enter the design into the machine and wait for it to finish. When it comes out to your satisfaction, you can go ahead and make all the silicone wristbands you please.