How to HMAC-SHA256 decrypt/encrypt?

Authorization: AWS4-HMAC-SHA256 Credential=EK036A7USWCWH58AI2BF/20210720/*private*-content-sha256;*private*date;*private*user-agent;*private*, Signature=4feda34a4ba5acf96c05c82dd8241f08e95052fe1f00c557a3aec5fba2695937

I want to understand what the HEX and Base64 fields require in the Hash/Hash String block. Would also like to know the hash for the Signature parameter.

Thank you very much.

Thank you very much, boss.