From your Shopify admin, go to Online Store > Themes.
Find the theme that you want to edit and click Customize.
In the left-hand toolbar, click Theme settings.
To offer multiple currencies on your online store, you must first edit your store's currency formatting.
Format: choose whether to include currency descriptor, such as USD or CAD, with the converted currency.
Show Currency Switcher: check or uncheck to show currency picker on the storefront so that customers can change to display in a currency they like.
Currency Converter Engine:
Shopify JS: default. It will be explained more details below.
Shopify Payments: If you pick "Shopify Payments", you can refer to this article for setting up multiple currencies.
The only affect when you pick the currency converter engine is "Shopify JS". Even though prices are displayed in different currencies, orders will still be processed in your store's currency. Clear your browser cache to see your changes.
Enable Auto Currency Converter: check or uncheck to all the prices will be adjusted to the country of your customer.
Supported currencies: enter currencies that your store is using. Use the country's ISO currency code. Separate your currency codes with space.
Default currency: enter currency default on your store.