By default, merchants can customize using the Default collection template.
The same as product template, with the new update that is compatible with Shopify Online 2.0, merchants can add a new template directly to the admin page rather than the default.
1. In the theme editor (Customize), use the page selector to open Collections > Create template.
2. Add Name in the provided field for the new template.
3. Choose the suitable value in the Based on dropdown, then select Create template.