Within the WooCommerce plugin, there is an option to import and export data in a CSV file. This means you export all data from here and can work on your warehouse inventory out of WordPress, for example in Excel, then convert it back to a CSV file, and upload the data to the Stock Manager again.
Obviously it is necessary to respect certain conditions for data transmission, which are explained in detail on the main page, see the picture below.
All the information in the CSV file regarding the stock and its status must be in accordance with the scenarios described in more detail in Stock editing article, otherwise the values will be ignored and will not be stored in the WooCommerce Stock Manager.
More plugins for WooCommerce from Toret