The use of text-generating Large Language Models (LLM), such as ChatGPT, in scholarly writing presents challenges to transparency and credibility. Journals and institutes are in need to revise their policies on whether the usage of such tools is acceptable throughout the research workflow and to provide guidance on how to safeguard transparency and credibility when LLMs are allowed to assist researchers. The present practical guideline should help those scholars who use LLMs and journals and institutes that allow using them. We also provide an example text to show a transparent usage of ChatGPT.