Yes, if configured, Metadata fields are sent to translation out-of-the-box.
Per the Documentation:
You can control which Text fields and External Link fields are sent for translation in Schemas by selecting the Translatable check box in:
- Schema fields
- Embeddable Schema fields
- Schema metadata fields
- Multimedia Schema metadata fields
- Metadata Schema fields
- Bundle Schema metadata fields
The Translatable Content topic covers the translateable item types, which includes text, rich text, and external link fields:
Translatable Metadata fields
If the following Content Manager items have metadata fields of type Text field, External Link field or Format Area field, you can send these fields for translation:
- Multimedia Components
- Structure Groups
- Virtual Folders
Having noted this, keep in mind that though using Page metadata specifically for translateable content is indeed a supported feature, this reduces centralized control over a Page's Component Presentations.
See Manuel Garrido's thought leadership on minimizing localizations or his post on BluePrinting and translation.