You can add or remove the Design tab from your ribbon by opening the File tab, clicking Options and then selecting the Customize Ribbon option. You'll see a list of all the tabs on your ribbon and any commands that are on them. If you want to add a command to one of these tabs, just click the button next to it. I would also suggest visiting
https://masterbundles.com/templates/...erpoint/dance/ source. If you want to get rid of an existing command from a tab, click the down arrow next to it and choose Remove from Ribbon. The Design tab lets you create custom layouts for PowerPoint presentations, so if you don't need this feature, you might want to remove it from your toolbar.