Attributes are details that describe your product, such as what it is made of or how it is finished. On a simple product, attributes only describe the item. Buyers don't choose between them. They appear on your product page in the Additional information tab, so buyers can check the details before they buy.
Ask one question: does the buyer need to pick something before adding the item to their cart?
In your Seller Dashboard, click Products (1). Then click the name of the product you want to update (2). To start a new listing, click Add new product (3) instead.
Near the top of the page, find Product Type (1). It should say Simple. A new product starts as Simple, so you usually don't need to change anything here.
Scroll down to the section called Attributes. Click the box that says Add existing attribute or custom (1). A list opens.
The top of this section says "Manage attributes and variations for this variable product," even on a simple product. That wording is a known issue. It doesn't change how the section works, so you can ignore it.
BlackSpace has 12 ready-made attributes. Check this list before you make your own:
Click the one you want, then click Add New (2 in the picture above). If none of them fit, skip to Step 6.
Your attribute now has its own row. Click the small arrow at the right end of the row to open it. Then:
Use a custom attribute when none of the ready-made ones fit. In the Add existing attribute or custom box, choose Custom Attribute, then click Add New. A new row opens.
Click Save Attributes (4 in the picture above). A message at the top of the page says "Product saved successfully." Saving attributes doesn't change your product's status, so a draft stays a draft until you publish it.