Nick here from Shopify. Can you elaborate a little more on what you mean, please? I'm not 100% sure what you're asking when you refer to an app being on the shelf. Any extra information, screenshots or examples would be hugely appreciated.
Looking forward to hearing from you.
All the best, Nick
No problem at all.
Ah ok, I'm not 100% sure on how long it takes, but your best bet is to follow the guidelines on making an app and submitting it. You can see the help guide Shopify made for this here. Once you have submitted your app, the Shopify App review team will take a look and review it as soon as they can,