This is a critical step for rigorous review papers, such as systematic reviews. Documenting searches for traditional (narrative) literature reviews is not essential but will help you stay organized and perhaps save you some time.
Consider whether it makes sense for you to document the following during your search process:
We recommend that you document your search strategies using a tool with which you're comfortable. Commonly used tools include desktop or web-based word processors and spreadsheet software. Web-based software (e.g. Google Docs or Google Sheets) should be considered for collaborative projects.