This article shows you how to export and import annotations (ink, line, rect, ellipse, note) from a page to another.

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    //get first page
    PDFPage *page1 = [m_doc page:0];

    [page1 objsStart];    

    //get last added annotation
    PDFAnnot *annot = [page1 annotAtIndex:([page1 annotCount] - 1)];    

    //save annotation data and export
    PDF_RECT rect;
    [annot getRect:&rect];    

    unsigned char buf[1024];
    [annot export:buf :sizeof(buf)];    

    //get second page
    PDFPage *page2 = [m_doc page:1];    

    //import annotation to the second page
    NSData *data = [NSData dataWithBytes:buf length:sizeof(buf)];
    [page2 importAnnot:&rect :[data bytes] :data.length];

You can change the buf size based on your needs.