You can get to this part of the system by clicking on the Products link in the blue Admin Toolbar and then clicking on the Bulk in the drop-down bar.
Critical Prerequisite: Before you do any bulk spreadsheet uploads, please review this article with tips and tricks that you will need to know to make sure you aren't making damaging changes to your data. This link will open in a new tab for you.
Edit Quantity and Cost for Saved Inventory
If you need to adjust inventory count and/or cost for inventory that is already saved, you can do so from this area. First, click the Spreadsheet drop-list and click on the Edit Existing Inventory spreadsheet. Then click Download.
You can open this CSV (comma separated values) file in any spreadsheet program, or in web applications such as Google Sheets. Once it's open, please note that most of the columns are for reference only. Only columns K and L are for editing, so if you make changes anywhere else, they will not upload into the system.
You can update inventory quantity count in column K, Edit Inventory. You can add or edit Cost data in column L, Edit Cost. Once you have made your changes, save the spreadsheet in the same CSV format.
Go back to Products > Bulk and make sure the Edit Existing Inventory spreadsheet is selected in the list, as above. Click the Upload link and you'll be able to upload your changes. They will go into the products immediately, but may take a few minutes to propagate.
Add Cost to Items That Have No Cost
The Bulk section of Products has a very convenient spreadsheet for finding and fixing any of your inventory items that do not yet have Cost values saved. You will want to have Cost values in the system for all of your products so that your profit margins will be accurate.
Go to Products > Bulk and click the Spreadsheets drop-list. Scroll down to the Edit Cost for Inventory with No Cost spreadsheet and click it, then click the Download link.
As with the previous spreadsheet, most of the columns in this sheet are for reference only. The only column that will upload edits is column G, Cost. You can open the CSV file in any spreadsheet program or online tool, such as Google Sheets. After you have added your costs to column G, go back to the Bulk area of Products and make sure the Edit Cost for Inventory with No Cost spreadsheet is highlighted, then click the Upload link. Your Cost values will be saved in their respective products immediately, though the changes may take a short while to propagate across the servers.