Hi Bruno123

Congratulations on your new Ipad. Im sure it will be an indispensable tool for you not only for music but also for other things. First off, I also had a lot of lyrics in Word format. One easy way is to convert all of these into pdf. I think Word allows you to do this as a "Save As" option.
Then you could load all of these files into the iBooks app which ia available free on the itunes store. The newer version of iBooks allows you to create folders as well. Here you can store all your lyrics and call them up on the fly as you play. This is one method you could use when you play and use the iPad for your lyrics.

Cheers

Sunny