Gayle,
You can download the commercial version of the library from “My Account” Page. Replacing the trial version of library in your project with the downloaded commercial version (canvasjs.min.js file) will remove the trial version text. We suggest you to clear the browser cache after replacing the script.
If you are still facing issue in downloading commercial version or for further license related queries, please contact sales[at]canvasjs[dot]com.
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Suyash Singh
Team CanvasJS