Meta recently launched an update called "Adapt to Placement", which allows for designs in multiple formats (aspect ratios), adjusting to fit each placement perfectly.
So you can have a designated 1:1 feed design, a 9:16 story design, and a 4:5 feed design all in your catalog images - making sure your ad looks the best in each placement - no more cropping or white space.
Each of your design variants can now hold up to 3 formats.
The first step is to go into your "Designs" tab, and add the formats you wish to use for all your active designs.
Once you open a design, click the "Formats" option in the bottom left of the screen to navigate between these formats, add new ones, and edit them.
The system will automatically pre-generate the format for you based on the 1:1 - make any adjustments you want and click "Save" in the top right.
Next, go into your Meta catalog and click "Edit".
Inside this page, click the gear icon in the top right and go into the "Formats" tab - here, you can choose which formats you wish to use (1:1 is mandatory; 4:5 and 9:16 are optional).
As long as every single variant in your catalog has the formats added (if there are designs without all the required formats, you'll see an error - you can add the formats into that design as well, or archive it), you may click "Save" in the top right corner.
You can refresh the catalog manually in Confect, followed by Meta, or wait for a few hours to guarantee that Meta has downloaded and processed the new formats.
The last step to adaptive Catalog Ads is to go into your ads and enable "Adapt to Placement" under "Advantage+ creative" (do not enable any other Advantage+ creative options).
Save this, and publish your ad.
It is up to you whether you want to enable this for all your catalog ads or just a select few.