i understand the technology and i understand how it helps in two domains which are voting and currency but i don't understand how the Blockchain helps in other domains such as health care or supplychain, i mean what is wrong with today's health care and supplychain !
Short answer: Nobody can give such an example.
Simple reason: Collaboration existed long before blockchain was invented.
Satoshi Nakamoto started chapter 12. Conclusion of his paper with the sentence:
We have proposed a system for electronic transactions without relying on trust.
If you take a deeper look into the technology you realize trust got in fact replaced by distributed computing power. Causing another problem. Namely, how to distribute this computing power in a trustworthy way.
Since voting (as we usually do in democracies) and health care heavily rely on trust in the persons involved I find it difficult to see any reason why and how a blockchain could help in these fields.