where change product size attribute radio button checked size ?

Hello,

First of all thanks for choosing our Theme, we are glad to be you in the WoodMart WordPress family :-).

Please elaborate with the help of some relevant screenshots of the specific area with the URL of the page that you require because your current explanation is not clear enough to understand what you require.

Regards.
Xtemos Studios.

Hello,

I saw the screenshots you attached.

Please read our detailed documentation in the following link:
https://xtemos.com/docs/woodmart/variable-products-swatches/

Best Regards.

Hello,

I saw the screenshot you attached.

Sorry, but it is not possible to make the design the same as you mentioned in the image of your reply.

Therefore to add a border around the variations try adding the following Custom CSS in the Global Custom CSS area under Theme Settings >> Custom CSS.

.woodmart-swatch.swatch-on-single {
    border: 1px solid blue;
    padding: 10px;
}

Best Regards.