What is “export order”? I also have other sales channels and I want to effectively manage my inventory. Can I export orders?

Each order category features an “export order” function that can be used to export all the orders under the category as a CSV file, giving designers added convenience when managing shipping and inventory.

A CSV file is a type of plain text file. After downloading it, you can copy the data from the file into an Excel spreadsheet.

If the file you have downloaded appears garbled, you can check the following links:
How to Open CSV Files - Mac
How to Open CSV Files - Windows