Light is emitted in packages
From any source, be this a star or a bulb or a laser or something else, light is emitted as quanta, later called photons. This has to do with the excitation of subatomic particles, mostly electrons. They absorb and re-emit photons.
Photons are indivisible units and as you stated well they have an oscillating electric field component and an oscillating magnetic field component. Because of the existance of this field components photon radiation is called also electroagnetic radiation (EM radiaten).
EM radiation and EM waves
For electromagnetic radiation from thermal sources it isn't possible to measure a common for all the included photons oscillation. Their time of emission is randomly distributed and their electric and magnetic field components are pointing by 90° to each other but they are equally distributed all over 360°. That is why stars emit EM radiation.
An EM wave you get from an antenna where the photons get emitted nearly at the same time, all are polarized and the emission itself is with an oscillating intensity.
Energy content of photons
Photons are indivisible, always have the two field components and all are moving with the speed of light. But the are distinguishable by their energy content. The greater the energy content the more energy will be realized than the photon gets absorbed. The same amount of infrared photons will heat a black body less than ultraviolett photons. In this sence one can talk about the photons intensity. Intensity is not a dimensional property, it is a quantitative property.
Intensity and amplitude
The theory stated that electric and magnetic fields are extended to infinity. To talk then about an amplitude like for water waves makes no sense.
A photons can go through a wide enough slit undisturbed. The smallest slit for which this is possible is somehow associated with a cross section of a photon and not with an amplitude.
But there is the famous double slit experiment there the intensity of an incomming EM radiation gets converted into an intenisty distribution behind the slits. The intensity of each fringe is measurable and if one draw a graph this graph will looks like a wave. It is stated that the amplitude of this graph and the intensity of the light are related.
Intensity of EM radiation and of photons over distances
A far away star emits photons in all directions. Over distances this EM radiation gets weaker and weaker. To collect the light from stars billion light years far away from us one exposure the measurement instrument by hours to collect enought photons. So the intensity of EM radiation decreases other distances.
Photons are indivisible units and the travel through space invisible (without interaction) as long as they not hit matter, for example the measurement instrument. Since the photon does not lose energy during his travel, the intensity of the photon stays the same.