If you sell on Walmart.ca you can upload your products with English descriptions and titles but Walmart expects you to translate it to French within 3 months. If this requirement is not met Walmart may unpublish your products.
It is recommended to have a professional translator to convert your English descriptions to French, however as an alternative or temporary option you may use Google Translate. It is not a perfect solution, but it works pretty well and Walmart allows users to use this method for translations of product descriptions.
The formula to use in your Google Spreadsheet is:
=GOOGLETRANSLATE(text, "source_language", "target_language")
To translate text in bulk, create two columns. The first one with English text, and the second one with a formula in a cell B1:
If you now populate this formula down the column B, Google will translate your text.