- Open Settings > Metafield definitions.
- Choose Add definition.
- Choose the resource the field applies to.
- Enter a merchant-facing name, namespace, and key.
- Choose the value type and any limits or validation rules.
- Choose translation, storefront, search, and filter options when the selected owner and type support them.
- Save the definition.
Text, numbers, true or false values, dates, date and time values, JSON, URLs, select choices, and file, product, or variant references are supported. List variants are available for supported types. The form only offers capabilities valid for the selected owner and type; the server enforces the same rules on every write.
You can later change the name, description, validation rules, display order, and eligible capability settings. Tightening validation affects future writes; it does not silently rewrite existing values.