Although these are most basic concepts for security, it’s not uncommon hear people using these two terms interchangeably.
Encoding : Convert data to some other representation –so that it abides by target expectation/protocol. Data transported over HTTP, FTP, compressed files –all are encoded , such that, on arriving at target, HTTP protocol, FTP protocol and compression utility get data in which they can process.
Encryption can be as simple as “Reorganizing” the data –Adding some header, footer etc. or it could be conversion of character to some format –But the intent is not “securing” Data.
Encryption: Encryption could be encoding, but not vice versa. Intent is secure transfer –only intended recipient can decipher the data. It could be just simple encoding or it could use complex cipher algorithm and keys to abide by encryption.