If you have been approved for 2-Day Shipping on Walmart, you do not need to do anything in Listing Mirror. Instead, you will want to apply this shipping speed through your Walmart Seller Center account.
Here's what you need to do:
Select Shipping under Settings
Under 2-DAY SHIPPING, you'll see options for which listings to apply your shipping to. This will vary depending on what you're able to commit to.
Step 3 & 4
Make sure to select a time zone, the dates that will be exempt from regular business hours, and your shipping policy that will be applied to your listings.
If you have questions about this process or if it isn't working as intended, please reach out to our support staff for assistance.