With regards to the communication process, which term refers to the conversion of a sender's ideas and thoughts into a message, usually in the form of words or signs?

Encoding.

Explanation:

'Encoding' is demonstrated as the process in which thoughts, ideas, or messages are converted into a message or communication in the form of signs or words that needs to decoded by the listener/receiver in order to understand and interpret it. It is basically associated with the formulation of messages (in the form of words) that a person wishes to convey to another. The efficacy of encoding is determined by the choice of words and the style in which it is arranged or presented as it is directly related to the receiver's interpretation of the meaning. Therefore, 'encoding' is the answer.