It really varies by project and also depends on the context. Plus, on some projects it makes sense to combine them and take what is referred to as a hybrid approach.

For projects which need a short delivery timeframe and that need to deliver value quickly and often go Agile. Agile is better suited for requirements around lean documentation and Governance as well.

If the project requires more hard deadlines, hard approvals or stage gates, can’t have variations on scope or deliverables then go Waterfall. Waterfall is better suited for projects that extend over longer periods of time.

In some projects you might go Waterfall during the Planning phase and you might switch to Agile during the Delivery or Execution phase.