Sync logistic is used to input logistic courier info into your order invoice in POS.
DealPOS Marketplace will scan every active courier service from your marketplace channel that you can sync to POS.
If you want to know which courier services your customer chooses, you may want to set up this setting. But this is optional and not a mandatory set-up, it depends on your needs.
Step 1. Add Courier Service SKU (Marketplace)
Step 2. Create Product (DealPOS) for Courier
Create Courier Service as Product Non-Inventory in POS and make sure SKU is the same with Marketplace SKU.
Step 3. Recheck Product on Invoice Detail
You might want to read these articles below :
You can also read about how to Configure Marketplace Channel
If you want to go back from the beginning, you can read about Introduction Product Marketplace
To synchronize inventory stock manually, the explanation is in this article : Manual Inventory Synchronize