MCL Mangai is a popular "legacy" Tamil font. Before Unicode became the global standard, different developers created their own encoding systems to display Tamil characters. MCL Mangai was widely used in desktop publishing (DTP) and print media because of its beautiful calligraphy and clean aesthetics.
Some converters struggle if your text has English words interspersed. It is often best to convert Tamil sections individually. Mcl Mangai To Unicode Converter
Well-known for their robust conversion engines. MCL Mangai is a popular "legacy" Tamil font