Most public-sector systems don't fail audits because of missing features. They fail because nobody can answer a simple question afterward: who changed this record, and when? Audit-readiness is mostly a design decision made before the first line of code, not a feature bolted on at the end.
In practice this means every write to the database carries a user, a timestamp, and a reason where relevant; approvals are recorded as a trail, not just a final status; and reports can be regenerated for any past date, not only "right now." None of this is expensive to build in — it's expensive to retrofit.
When we scope a government system, we ask what a reviewer will ask for a year from now, and build the logging around that answer, not around the happy path of daily use.