Shopify themes are a collection of pre-made layouts, modules, and style options that control how your website will appear and feel. Off-the-shelf themes, or turnkey, pre-designed templates, let you effortlessly customise built-in modules to make a lovely e-commerce website. Based on their general appearance and functionality, pre-made themes come in a variety of free and premium versions. You can choose from a number of theme choices that are most suited for the kinds of things you sell, your branding, your business, or the kind of experience you want your clients to have when visiting your online store.
Then there are the custom themes, which can be made with a developer's assistance. Custom themes can be created from scratch, or further customised versions of pre-made themes can be added to support higher-level functionality or looks.
How to Use Shopify ThemeVisit the Shopify Theme Store and choose a Free/paid theme.
Click Try theme to add the theme to your online store.
In your Shopify admin, click Online Store > Themes.
In the Theme library section, click the ... button to open the actions menu next to the theme that you want to preview.
Click Preview.