Q: What is conceptual technique?
Your query isn’t really clear. It’s not clear if you wish to know about conceptual research, the conceptual framework, a concept paper, or something else.
In case your query is around conceptual research, it basically refers to research conducted based on observations rather than through experimentation. (The latter is known as empirical research.)
In case your query is around the conceptual framework in research, you may refer to the following resource: What is conceptual framework in research?
And finally, if you wish to know about a concept paper, you may go through this resource: What is a concept paper?
Hope that helps.