Elias here with Shopify Support. Thank you for reaching out!
The notification email and SMS templates are located in the Notifications settings (Settings > Notifications), where you'll find a series of notifications sorted into categories. After you choose a certain notification to edit, you can switch between the email or SMS templates.
If you're not familiar with coding, don't worry - Simply work around the variables in brackets. As an example, I've underlined the text that can be translated in the following screenshot. You can also use the Preview or Send test email functions to help get an idea of where you need to translate and see how your translations are appearing. Incase there's a mistake, there's a button at the bottom to revert the template back to default as well.
If you're not comfortable with making coding changes, you can hire a developer to help you with that. Shopify Experts is a directory of experts that are well-versed with custom coding and they'll be able to help design a unique template for your store.
Let me know if this is what you're looking for?