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As a new seller, you might have been started with the Quick Lister (which does not support variations at all). If so, click the option at the top right of the listing screen to switch to the Business Lister. If you were already listing with the business tool and have been switched to the new Unified Lister, the variation option must be turned on at the top of the tool.
On the new Unified lister, click the triple dots up there and and select the gear icon to open more settings.
The variation option can be turned on with that setting, but ONLY if you have already selected a category that supports variations (if not, the option will not appear). Once you are able to turn on that feature, any future listings in categories that support variations will display the "create variation" button. Categories that do not support variations will hide that feature.
