An important step in designing a monitoring and evaluation plan is selecting key indicators to measure progress or impact. The indicators should reflect the changes you expect to see as a result of your programme, and they could emerge from your theory of change. Indicators can include both the ultimate changes you expect to see (such as reduced use or experience of violence) and intermediary factors that affect these outcomes (like couple communication or attitudes about violence).
While we often think of indicators as quantitative or numeric, they can be more qualitative or descriptive; the key is to match your indicators to the type of evaluation methods that fit your programme well. There are many examples of standard indicators or measures that you can draw on, but it is important to tailor these to the programme and implementation context.