* L'instruction en famille: This is the most common and generally accepted term. It literally translates to "family instruction."
* L'école à la maison: This means "school at home" and is also understandable.
* Éduquer ses enfants à la maison: This translates to "educating one's children at home" and is a more descriptive phrase.
The best option will depend on the specific situation. For official documents, l'instruction en famille is likely the safest and most widely understood.