How Can I make an Admin Section without using a database in my web project?

Few Months Ago I worked on a web project. The Project Included a personalized Webpage for an organization. I didn't used any CMS back then. But now, at present my employer wants an Admin Panel for that previous project. How can I make an admin panel for that project I previously worked? and

Note that I didn't use and database integration for my web project. So can I develop an Admin Panel without database so Admin can update the content of the website dynamically?