I don't see an option in the document templates directly, so you might investigate the word merge module from the appstore:
https://appstore.home.mendix.com/link/app/2026/Appronto/Word-Document-Merge-4-Mendix
Alternatively you could try to implement your own merging in java, see below for some starter code that will merge 2 docx files when given as inputstreams:
public static void merge(InputStream src1, InputStream src2, OutputStream dest) throws Exception {
OPCPackage src1Package = OPCPackage.open(src1);
OPCPackage src2Package = OPCPackage.open(src2);
XWPFDocument src1Document = new XWPFDocument(src1Package);
CTBody src1Body = src1Document.getDocument().getBody();
XWPFDocument src2Document = new XWPFDocument(src2Package);
CTBody src2Body = src2Document.getDocument().getBody();
appendBody(src1Body, src2Body);
src1Document.write(dest);
}
private static void appendBody(CTBody src, CTBody append) throws Exception {
XmlOptions optionsOuter = new XmlOptions();
optionsOuter.setSaveOuter();
String appendString = append.xmlText(optionsOuter);
String srcString = src.xmlText();
String prefix = srcString.substring(0,srcString.indexOf(">")+1);
String mainPart = srcString.substring(srcString.indexOf(">")+1,srcString.lastIndexOf("<"));
String sufix = srcString.substring( srcString.lastIndexOf("<") );
String addPart = appendString.substring(appendString.indexOf(">") + 1, appendString.lastIndexOf("<"));
CTBody makeBody = CTBody.Factory.parse(prefix+mainPart+addPart+sufix);
src.set(makeBody);
}
Be aware that this will add the content of two word files into 1, but needs work on the margins for page 1, so not there yet but maybe a starting point for your app.