It says

Bocchi za rokku Arigatou gozaimashita!

Bocchi za rokku is the name of the series (Bocchi the rock)

And the ri/i thing is just a handwriting thing. You can tell it's meant to be ri because the right side is much longer than left side

Edit: also, warra wouldn't be translated as laugh. The stem of verbs can't stand on their own. You will only see warau (laugh) as warai, waratte, warayou, etc., but never as just wara. It also wouldn't really make sense to make wara into warra. Some people will add the tsu to emphasize certain syllables, but in this case, it would just end up sounding weird and unnatural. And plus there's no real reason to emphasize syllables in this case