Whilst I'd go with what Pixel is recommending, even the Morrowind Overhaul 3.0 does a fantastic job of updating the game graphics and enabling widescreen support. However, the Overhaul is a bit dated now (2012 release) and you can do a better job of improving the game via the links recommended.
I would also consider looking at Tamriel Rebuilt, which adds the mainland province of Morrowind to the game, expanding the world beyond Vvardenfell. This is still a long term project but, they have added a huge amount of content.