The Future Work sections has continuing work that a project immediately following yours would undertake.
Generally, include a few (2-3) topics along three different tiers:
Short term - immediate parts of the work that would be started, such as continuing with development or analysis that was not quite completed.
Medium term - work over a few months that continues the project work you started.
Long term - more extensive work that fits in with the overall goals of the project space, but is probably beyond the scope of even another whole project.
You do not necessarily need to break them up by tiers, but you can certainly think of them that way.
For most reports, the Future Work chapter would include a half-dozen such items total.
For each future idea above, write a short paragraph providing a few details on what the work entails. A general "formula" for this paragraph that works well is:
Open with the future work item itself. e.g., "Future work includes doing XYZ..."
Say why that item is interesting. e.g., "Doing XYZ would allow someone to do or know ABC ..."
Briefly sketch out how you would go about tackling this future work item yourself, should you have to do so. This is typically brief, just a quick sentence or two.
Overall, the future work should not make it look like the best and most interesting parts of the work are yet to come - the project itself should be viewed as cool and significant (e.g., in the Conclusion chapter).