Making revisions to or adding new material to an existing web page is often an overlooked part of maintaining a website. Make it part of your routine to look through your site every couple of weeks or so to see if anything new can be added.
Be careful not to change the primary focus of a page when you’re adding new material. Hopeful your web developer optimized the page for search engines based on it being focused a particular way. Adding too much content can change that focus in the eyes of the search engine (and probably for your visitors too).
It might be that the content has changed sufficiently and the page should be re-optimized, but that will be a fair amount of work. Always see if you can add the material with different wording, perhaps or maybe it’s worth filling out the new content more and creating a new page altogether.
Remember, content is King to your visitors and search engines.