How to enable swatches globally to all variable products?

Yes,It can be done by using global attributes so merchants just follow these simple steps.

1: WooCommerce-> product->attribute.

2: Click on attribute(color)-> then all variations are listed (black,blue,black-silver,black-green etc).

3: Click on configure terms->as you click on that, all variations will list.

4: Select any variation -> click on edit(button)-> there is an option “Display Type” from there you can select the thumbnail-image/color/text which you want to display on the front end.

5: Now this setting works globally for all global attributes and swatches will show on all products.