Most of the examples below use the "product" scope. To use metafields for other object types, just replace "product" with your required scope for the template such as "collection", "customer", "page", "shop" etc.
By default, all custom fields are defined using the namespace "accentuate". You can override this on a field-by-field basis by specifying another namespace, which will then be used when storing custom field values. Please take care when choosing a namespace, so it doesn't collide with other apps' namespaces