There's many organisations willing to charge you plenty of money to learn about Blockchain, but here's some resources that don't cost you a penny to access:
Bitcoin & Cryptocurrency Technologies eBook - Princeton University
Blockchain Innovation Podcasts
Blockchain Tutorial: How To Become A Blockchain Developer - Blockgeeks
Blockchain: Understanding Its Uses and Implications - The Linux Foundation
Blockchain for Business - An Introduction to Hyperledger Technologies - The Linux Foundation
