If you want to export inventory, 

1. Choose 'Seller Center > Inventory'

2. Choose 'Create > Export' from top right hand corner

3. Click 'Confirm'

4. From 'Recent Jobs', wait until the batch export to complete

5. click download button on the right hand side to download the file

The file looks like this.

Note 1: If you have multiple warehouse / location, you can choose that at step 3.
Note 2: The file can be used for batch update inventory through re-importing.