By placing a watermark on images that you plan to post on the web, you identify those images as your work and discourage people from copying or claiming your work as their own. Here's an easy way to add a watermark in Corel Photo-Paint 2020 on macOS 10.15 (Catalina) and should be similar on other versions and platforms.
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While there is no one-click option to create a watermark, the steps below are simple and offer plenty of formatting options.
Select the Text tool from the toolbar on the left.
In the properties bar, set the font, text size, and formatting of the watermark.