Use the personal author(s) or editor(s) if listed on the report, otherwise use the group author name.
National Institute for Health and Care Excellence (NICE, 2020) state that......
...(National Institute for Health and Care Excellence (NICE), 2020).
NICE (2020) acknowledge that....
Note: A good tip if you are going to use the same citation a few times in your assignment is to use acronyms. You must explain the acronym in full the first time you use it, followed by the acronym so it is clear to your lecturer what the abbreviation stands for.
Last name, Initial(s) or Group Author. (Year). Title (Series or reference number if available). Publisher. URL
Knight, M., Bunch, K., Tuffnell,. D, Shakespeare, J., Kotnis, R., Kenyon, S., & Kurinczuk, J. J. (Eds.). (2020). Saving lives, improving mothers’ care: Lessons learned to inform maternity care from the UK and Ireland confidential enquiries into maternal deaths and morbidity 2016-18. MBRRACE-UK. https://www.npeu.ox.ac.uk/assets/downloads/mbrrace-uk/reports/maternal-report-2020/MBRRACE-UK_Maternal_Report_Dec_2020_v10_ONLINE_VERSION_1404.pdf
Mid Staffordshire NHS Foundation Trust Public Inquiry. (2013). Report of the Mid Staffordshire NHS Foundation Trust Public Inquiry: Executive summary (HC 931). Crown. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/279124/0947.pdf
National Institute for Health and Care Excellence. (2020). Type 2 diabetes in adults: Management (NICE Guideline NG28). https://www.nice.org.uk/guidance/ng28/resources/type-2-diabetes-in-adults-management-pdf-1837338615493
NB: When the author and publisher are the same (as in the example), omit the publisher name to avoid repetition.