It can convert formatted text directly within MS Word. If your MCL Mangai document has bolded headings or tables, Azhagi+ preserves them while changing the text to Unicode (which you can then set to Marutham).
Paste your MCL Mangai text into the source box, select "MCL Fonts" as the input, and choose "TAU Marutham" or "Unicode" as the output. Azhagi's Tamil Font Converter mcl mangai to marutham font converter top