Encoding changes a representation so systems can transport it: Base64 or URL encoding can be reversed by anyone. Encryption protects confidentiality with a key, and sensitive data should normally use authenticated encryption so tampering is detected too. Hashing maps data to a fixed-size digest; a checksum can detect accidental changes but does not prove who created the data.
Passwords need a dedicated, salted password-hashing method, not a quick generic hash. If you need authenticity between systems, consider a MAC or digital signature rather than assuming a hash alone is enough. Choose the mechanism based on the goal: transport, secrecy, integrity, or identity. Converting bytes to Base64 is never a security boundary.
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