You will need to provide a reference to RevMan in the list of references of your Cochrane Review or other publication. RevMan should be cited as:
Review Manager Web (RevMan Web). Version (version number). The Cochrane Collaboration, (version date). Available at revman.cochrane.org
The below screenshot shows how this reference can be added as an Additional reference in RevMan.
Please check the version number and date in the RevMan Help Menu: Help > About.