What angle? The perspective of the moon changes:
img
How does this make sense if the moon and the sun are far away and don't change distance to the observer?
The graph shows how aspects of the Moon change depending on location of observer and its position in the sky. It's not a graph of how the Moon changes over the period of (say) one night.
They do change distance, but only slightly in galactic terms. The observer on Earth could, if at the equator, move to and from the Moon and/or the Sun by up to half the diameter of the Earth.
However, this makes sense because, for the umpteenth time, you, the observer, are at one point of a triangle. The triangle is formed by you, the observer, the Moon and the Sun at the three points.
One face of the Moon is always illuminated along the imaginary triangle side connecting Moon and Sun. As the Moon moves around the Earth, this illuminated portion changes, as the same side of the Moon faces the Earth at all times. This gives us the phases of the Moon.
One side of the triangle is your observation line between you and the Moon.
The last side is the imaginary line between you and the Sun, but this is where it gets interesting, because after sunset, and before sunrise, you cannot take a bearing on this line, because you cannot see the Sun. It's below your local horizon.
However, because the Moon is 240k miles away from the Earth, the Moon is still in sunlight, even though you are not. Your local horizon is irrelevant to the illumination of the Moon.
The crucial thing to take in is that you, the observer, are most likely not aligned with this imaginary triangle. You're at one point of it, but you will most likely not be either horizontally or vertically aligned with the plane of it. This will affect what you see and how you perceive it. If you don't realise this fact, you will be confused by what you see.
This is why the image has the 'altitude' as one axis of the chart - that's actually the observer's LATITUDE on the Earth, isn't it?
I have a desktop globe, I have a little model Moon to go with it, I could make a 3D model to show you, but .... why should I, when folks here ask you to do the most simple of experiments (hold a small sports ball up to the Moon), but you apparently don't make the effort?