From your Shopify admin, go to Settings > Languages.
Click Add Language.
Choose a language from the drop-down menu, then click Add.
In Unpublished languages, click Publish beside the language that you want to make available to customers in your store.
Please install the Shopify Translate & Adapt app (Completely Free) provided by Shopify. This app will help you to translate different languages.
We usually put the Multi-Language function in the Header or Footer. Please customize it in the Section Header or Footer.