Showing “Powered by Plantix” is mandatory wherever you use the Plantix API in your app. This is part of the API Terms & Conditions (Section 8b, Attribution).

Usually the branding is shown while an image is uploaded and processed. You can also put it next to the button that starts the image analysis. Either way, the slogan and the logo must be clearly visible.
We provide .svg and .png files in different styles, so you can pick the one that fits your design best.