The best place to look is in the documentation - IBM Knowledge Center
Character data in the message is in the same character set as this structure; this is the queue manager's character set. (For MQMD only, MQCCSI_INHERIT has the same meaning as MQCCSI_Q_MGR).
The queue manager changes this value in the MQMD that is sent with the message to the actual character set identifier of MQMD. Provided no error occurs, the value MQCCSI_INHERIT is not returned by the MQGET call.
Do not use MQCCSI_INHERIT if the value of the PutApplType field in MQMD is MQAT_BROKER.
I've emboldened the relevant line.
You probably want to set MQCCSI_EMBEDDED and provide the character set identifier in the MQPUT call. (the next section down in the documentation after MQCCSI_INHERIT)