Documenting your search methodology is an important part of your research. This section can vary in length and detail but it will normally do the following:
Record your search strategy
Record the databases searched
Record any limits applied to your searches
Record numbers of results and number discarded and why
Record any websites searched
Record any journals searched & how (e.g. hand-searching or scanning tables of contents)
Record the date each search activity was done.
Two good examples can be seen here:
Look at the methods section in this article
Franke, H., Franke, J. D., & Fryer, G. (2014). Osteopathic manipulative treatment for nonspecific low back pain: A systematic review and meta-analysis. BMC Musculoskeletal Disorders, 15(1), Article 286. http://www.biomedcentral.com/1471-2474/15/286
Look at the Table 1 for a fully documented search strategy https://bmcmusculoskeletdisord.biomedcentral.com/articles/10.1186/1471-2474-15-286/tables/1
PRISMA is a flow chart tool used to document searches for systematic reviews and meta-analyses.