This investment mix shows what this fund holds (in teal): the proportion of growth assets (shares, commercial property, or other) or income assets (bonds or cash). You can compare it with the average mix for this type of fund (in grey).
It's important to know that this shows what the fund actually held in the most recent quarter, not necessarily what its target is over the long term. Fund managers may vary their investment mix depending on market conditions, so occasionally this can cause a fund to temporarily change categories (e.g. balanced to conservative).
As you invest, your mix (often called asset allocation) is the most significant factor that will determine the results you get, including the ups and downs in value you experience. Choosing a specific mix is a way of dialling your risk up or down, depending on the amount of growth assets you take on board.
For the most appropriate mix for you and your situation (often called your risk profile), see Sorted's investor kickstarter for managed funds, or answer these three questions for KiwiSaver funds.