When you enable any Add-in (like the Vevox PowerPoint Add-in), it adds custom commands and features (like polling) to your PowerPoint and helps increase interaction, inclusivity and productivity.
Should you no longer use Vevox and wish to remove/disable it from your PowerPoint ribbon follow these steps:
Open PowerPoint. Click File > Options > Add-ins
Towards the bottom of the window, where it says Manage, click the 'Go' button.
In the dialog box, select the add-ins you want to disable or remove.
To disable the Vevox add-in, just uncheck the box in front of its name. To uninstall the add-in select it and click 'Remove'.
Click 'OK' to save your changes and return to your PowerPoint presentation.
For further information to manage, install or remove Add-ins – check out this Microsoft document.