Products page is where you can see an overview of your current Shopify inventory in the default location you have set in settings.
Products are sorted in different tabs based on what information you're looking for. Order Now tab is what opens by default and contains products that require your attention:
out of stock products
products that need to be ordered now
products that will soon need reordering
Once a product is marked as ordered or snoozed, it will be hidden from this tab so you can focus only on the products that you need to take action on.