If it is just for Windows you can use either word or wordpad through the TOM interfaces (COM). Word does not work for Office365 in the cloud, though. Only a local install. But wordpad may be enough.
More cross-platform is OpenOffice or LibreOffice through XPCom.
Lightweight and also cross platform is Richmemo, ,or kmemo for that matter, which is a bit better than Tmemo or TSynEdit for Lazarus.