With Rocketium, this is just a one click activity. You'd see the 5 options below the Preview.
To go to the preview screen, hit CONTINUE, and you will see the screens below:
Landscape videos are more suitable for sharing on YouTube.
Portrait or vertical videos for sharing on Instagram Stories and Whatsapp.
Square for sharing on Facebook, Twitter and Instagram.
Facebook Cover Video for sharing a video as your Facebook Cover. [New]
Native Instagram Ads for sharing a video as an instagram native ad. [New]
You can publish your video in these 5 different aspect ratios depending on where you want to post them. If you want to create videos in all the 5 aspect ratios, the best practice is to create
clones of the original and publish it. This way, you'll retain the settings for the different copies, if you plan to edit them again.