Hyperledger

I highly recommend to do the Edx Course of Hyperledger for business from Linux Foundation, it goes from the basic theory of DLT and Blockchain, and even if you will dirty your hands with some code, programming with Fabric, Sawtooth or Iroha.
To get the certification you just have to pay 99$ and the course is split into 8 parts including a final exam.

Link to the course: https://www.edx.org/course/blockchain-business-introduction-linuxfoundationx-lfs171x
Happy Learning and Coding!