> ## Documentation Index > Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt > Use this file to discover all available pages before exploring further. # Extract activity > Extract data from documents using Document skills, and map each class from a preceding Classify activity to the appropriate Document skill. Use the **Extract** activity to extract data from documents using a Document skill. To extract from multiple document types in one workflow, place a [Classify activity](/vantage/documentation/skill-designer/process/classify-activity) before the Extract activity and map each class to a Document skill in the **Actions** pane. ## Set up Document skills Specify the Document skills that extract document fields: In the **Actions** pane, click **Add Skill** and select the skills you need from the **Skill Catalog**. If you can't find a suitable skill in the **Skill Catalog**, click **Create New Skill** at the bottom of the **Actions** pane. In the form that appears, enter a name, a short description, and a list of required skills, then click **Done**. Train the new skill and publish it to the **Skill Catalog**. Only published skills appear in the list of available Document skills. To view demo documents for a skill, click the icon to the left of the skill's name. If the skill has no demo documents, an error message appears — this does not affect your setup. ## Map Document skills to classes Map each Document skill to the matching class from the preceding Classification skill. Use one of two methods: * **Per-skill mapping** — In the **Actions** pane, click the properties icon next to the Document skill name. In the dialog, select the class that corresponds to the document type the skill processes, then click **Save**. * **Bulk mapping** — Click **Edit Mapping** at the bottom of the **Actions** pane. In the dialog, connect each class to a skill from your list, then click **Save**. ## Online learning If the Process skill includes a verification stage, enable **Online learning** for Document skills from the Preview window. Online learning uses verification results to continuously improve each skill's precision. See [Online learning](/vantage/documentation/runtime/online-learning/online-learning) for details. ## Skill parameters The Extract activity inherits skill parameters from the Document skill it uses. View or modify these values by clicking the skill-settings icon next to the Document skill name. See [Skill parameters](/vantage/documentation/skill-designer/skill-parameters/skill-parameters) for details. ## Related topics Identify document types and route each document to the correct downstream process. Extract field values from structured and semi-structured documents of a single type. Build a Process skill from a preset workflow or from scratch and configure each activity. Configure and manage skill parameters to adjust skill behavior without retraining. Continuously improve a published skill by retraining on new production documents. Assign a version number to a skill and make it available in the Skill Catalog.