This is the oldest piece of photography advice there is, and it is the reason your kids are squinting in every summer photo you own.
With the sun behind you, all of it lands flat on their face. They screw their eyes up because you have asked them to look directly into it. Shadows fall hard under the eyes and nose. Colours go harsh. Everyone looks like they are being interrogated.
Turn around and try putting the light behind them instead. Their hair lights up at the edges. Their face falls into soft, even light with nothing to squint at. The background goes bright and hazy and the whole frame softens.
Two things to know before you try it. Your camera will underexpose the face, because all that brightness behind them fools the meter, so push exposure compensation to plus one or plus two and let the background blow out. Nobody looks at the background. And if the sun hits your lens directly the image goes milky, so move a step so their head covers the sun, or shade the lens with your hand.
Try it once this week, late afternoon, and look at the back of the camera.