If you sign up for a Pro subscription, you can remove the branding card at the end of your mashes and the watermark on your snippets, among other cool features.
To remove branding only from the video you're mashing, do the following:
Tap the branding button at the bottom of the video editor. It reads "Branding On" until you tap it, then switches to "Branding Off".
Tap Save & Share, then pick an export quality.
Done! This specific mash won't display our branding.
On the iOS app:


