Altering the range of melee weapons

   I want to be able to alter the reach of melee weapons in blocks, in the form of a short range dagger and a long range spear. I understand this is far from an original idea, but as it is commonplace in many mods, I was hoping it wouldn't be too complicated for somebody to share a method of doing so. I've used MCreator for a while, but feel held back by my complete lack of knowledge of coding in java, which is severely limited to reverse-engineering and altering already existing code. I wouldn't known where to even start going about making this.
Thank you for taking your time to read this.