You can embed Twinmotion presentations into an iframe by logging into your Twinmotion Cloud web drive and selecting the presentation you want to embed. The embed code will displayed under the presentation details.
At this time, customization of the Presentation isn't possible, but this is being explored and is something we hope to add in the future. If you have any particular customization features you would like to see, please select the Feedback button on the bottom-right corner of the Twinmotion Cloud web drive and share your ideas with the team.