On mobile and desktop, the colour splatter has a purple background. However, following today’s update, the app icon will have a white background instead. Slack said in a tweet that this should make ...

You can edit a PowerPoint template by adjusting its theme settings ... You can also click the "Format Background" icon in the upper right hand corner to make these changes as well.

Though you can always choose a premade template, you may want to customize your PowerPoint slide backgrounds manually. You can add a custom background to one or more slides, and you'll also have ...