Hi @shaylenechino! Thanks for joining us in the Seller Community. Happy to have you on board!
When you're editing items from your Square Online Dashboard, you'll head to Item Library. Choose the item you're wanting to edit the stock for. Scroll down until you see Stock and select Update next to it. You'll want to make sure the toggle is ON by "Track stock" and make it so that you only have one of that item.
When customers are ordering from your site, that item will no longer be available once it's bought if you only set it to one.
Hope this helps! Feel free to reach back out with any other questions that come up.
