Yes "word art" in MS Word is probably the simplest way to do this, though it's not quite as easy in the newer versions as it used to be I think. If you want free tools, then LibreOffice Writer, the open-source equivalent of MS Word, has a similar tool called Font Work. To use that you have to display the Font Work tool bar via the View/Toolbars menu item.
For more flexibility, most vector drawing packages will have a function to fit text to a path, which could be any curve or shape. Adobe Illustrator as mentioned by Oliver is the most popular commercial application of this type. CorelDraw is one that I use. The best free equivalent would be probably be Inkscape.