Welcome to the community ​@sfawle

For a circle, create a circular image with the colour you want within the circle and on a transparent background*. Save as a png or GIF format so transparency is retained. Add that image to your form as the background image. You’ll need to change the form background settings to get that transparent. Below is an example preview of what it’d look like though the grey would trans when published.

Just round edges. Change the form styles ‘corner radius’ to get the look you want. That will only round the corners of the form, you won’t get a circle.

Hope that helps

Andy ​​​​​​​​​​​​​
* could use Photoshop or upload a square trans image and then use Klaviyo’s image editor (Shapes option) in the form editor to add a circle to that trans background