When you have multiple variants and want to use one particular variant as the Master variant, here is how you can do it.
When a variant is set as the Master Variant and the page is published, you will see the master variant on the live URL.
Please note that the Master variant can be set only when the A/B test mode toggle is in the OFF state.
At the bottom of the variant thumbnail, you will find the Three-dot icon. If you click that, you will see a drop-down menu.
In that drop-down menu, please select the "Set as Master" option.
As a result, the variant selected will become the master variant.
IMPORTANT NOTE -
By default, the first variant of the page will be set as the Master variant.
The Master variant can be set up or changed only when the A/B test mode is turned OFF.Once you have identified the winning variant for your campaign after conducting A/B tests, you can turn OFF the A/B test mode and manually set the Master Variant accordingly.