There are a few reasons why you might need to export your products to a CSV
To create a backup of your products
To move your existing products to a new Shopify store
To edit your products in bulk using a spreadsheet
Exporting products from Shopify
From your Shopify admin, go to Products
From the dialog box, choose the products you want to export
Select which type of CSV file you want to export
Click Export Products
For more information, visit Shopify's help article here.
Exporting products from WooCommerce
From your Wordpress admin, go to WooCommerce
Click CSV Import Suite
Select Export Products
After completing steps 1 - 3, you can then choose to export either products or product variations.
Note: The number of products that the Product CSV Import Suite extension will be able to export in one file is dependent upon the availability of server resources.
For more information, visit WooCommerce's help article here.