You can easily change the name and the description of your Moov. A description is not mandatory, but might be interesting if you publish a Moov to the Moovly Gallery, because its title and description are published as well.
To change the name and description of a Moov, click on its thumbnail to open the preview page:
To the right the video player, you’ll see various options such as edit moov, edit title etc.
Clicking the Edit title tab changes the view to 2 fields: one for the title and one for the description. Enter your text and click Save: