Hi, @axeltta .
Thank you for posting this question!
If you’re looking to offer a buy one get one promotion on your website, then we’d recommend using the the buy x get y discount feature instead as changing the default quantity selector to 2 units may not be the best solution. For example, changing the quantity selector will make it apply to all of your products, which may or may not be the desired outcome, and this may not provide the best customer experience.
Are you looking to offer buy one get one for all of your products? If so, then did you get a chance to check out our buy x get y discount feature already?