The answer is - it depends. The liquid most studied is water, which is polar. The bulk solution is isotropic - the polarity and forces are the same in all directions. The most common and most studied surface is the air-water surface - air is essentially non-polar, so the forces at the surface are unbalanced - resulting in surface tension. Is the surface layer different in polarity than the bulk? Non-polar substances will tend to go to the air-water interface if they do not dissolve in water - so that would make it appear to be less polar than the bulk.

But some of these considerations change if we change the liquid or the other phase. Air is actually very nonpolar - more nonpolar than any common liquid surface (more nonpolar than hydrocarbons or fluorocarbons, for example. There may be some exotic liquids - maybe liquid noble gases? - that are more nonpolar than air). So even with very nonpolar liquids, the bulk is more polar than the surface if the surface is with air. But if the surface is between two condensed phases (water and hexane perhaps or hexane and salt)? or what about a very polar gas like sulfur trioxide over a hydrocarbon liquid? Here the surfaces might be different in comparison to bulk - the salt-hexane surface would be more polar than the bulk hexane.

The questions you ask could take an entire semester on the thermodynamics of interfaces to address properly. One starting point might be to collect a few journal articles and reference books such as these ...

https://www.sciencedirect.com/topics/chemistry/liquid-solid-interface

https://onlinelibrary.wiley.com/doi/book/10.1002/9781444305401

Polarity is a measure of response of a dipole charge to an electric field. A general chemistry textbook gives sufficient basic information on secondary bonds and how they interact to learn the concepts. A fundamental approach from that point is to visualize the surface and the water molecule as charges and dipoles. Hydrophobicity/Hydrophilicity is a measure of a surface to repeal/attract water. The interaction forces arise due to differences or similarities in polarity between the surface and the molecule. In truth, a hydrophobic surface really does not repeal water. It is rather that a water molecule sees nothing polar enough to attract it. It is the same reason that a general chemistry lecture will teach that, without secondary bonds, we would have no liquids. The molecules don't repel each other, they just do not attract each other.

Finally, the polarizable of a molecule will change as it approaches a polar surface. This is because the electron cloud around the molecule changes its shape. This is not the same as saying the polarity of the molecule changes.

Please study I. Langmuir's early experiments (in the more comprehensive text books of physical chemistry) on unimolecular layers of insoluble fatty acids (e.g. stearic acid) on water. How and why he created them and measured the surface tension changes.

Yes ofcourse because unless the surface is polar where is question of its interaction with water which is polar. May it be surface or bulk that does not matter much.

In the gas phase, the dipole moment of molecules allows to compare their polarity. If we compare molecules on the surface and in the volume of the condensed phase, then in addition to the dipole moment, we should bear in mind their intermolecular interaction on the surface and in the volume. In volume, the forces acting on the molecule are compensated. At the interface, the forces are not compensated and this leads to an increase in the polarity of the molecules.

Non-polar solvents are only weakly attracted to hydrophilic silica surfaces, surface dipoles can interact strongly with adsorbed solutes, creating more polar environments than are found in bulk solutions. This effect was observed for silica/cyclohexane and silica/CCl4 in practice

I agree with James E Hanson