Project Budgeting and reporting

I work for an NGO running multiple projects, each with a specific budget, classified with different budget codes/ or lines. Critical for reporting purposes is the ability to prepare project specific budgets, which means the ability to apply a code to each line.

I tried to use a custom field as seen in the image attached.
Budget lines|690x315
however, no report can be prepared, and you can have an actual vs budget report.