The word "Bid'ah" literally means innovations. In Shari'ah, it means to introduce something new in Deen which was never done before and not part of Deen.
There are two types of innovations: a) Regarded as Deen – this is absolutely Haraam; and b) Not regarded as Deen, e.g. computers, technology, plans, etc. – this is not Haraam.
From this, the majority Ulama agreed upon this that there is Bid'at Hasanah and Bid'ah Sayyi-a.