Better be safe than sorry, Shir2! Even if you're not going to us an original track, it's better to get permission first.
Like, you're free to sing your new version privately to your friends and family members. But when you're posting it in the internet, then it might be considered as an unlicensed usage of the original work. Like, there are many of authors that don't mind covers since - with proper credits - they increase owner's exposure. While others might object the unlicensed usage of their work which leads to strikes and such.
Not sure if that's OK, but here's the really basic step-by-step on how to get a permission to use a song by Biteable. And here's an article by Dale Turner (his situation is different from yours, but still he mentions some sources that might be useful for getting permissions).