import { Header } from 'docx';
import type { DocxOptions } from './option';
/**
 * Create a Header containing a watermark.
 *
 * Uses a floating semi-transparent image positioned at page center with
 * behindDocument=true. Also adds a centered text paragraph as visible fallback
 * so that the watermark text appears in the header area regardless.
 */
export declare function createWatermarkHeader(watermarkOptions?: DocxOptions['watermark']): Promise<Header | null>;