What is the ruling on washing the area between the chin and the neck during ablution if there is a beard in that place, and is it obligatory to wash or comb through each part of the facial beard separately, or to wash the entire beard with a single wash?

What is under the chin does not need to be washed in wudu' (ablution), because it is not included within the boundaries of the face, and scholars have reached a consensus on this. As for the beard, if it is thin, it is obligatory to run water through it so that the water reaches the skin. If it is thick, washing its outer part is sufficient, and it is not necessary for this to be done with a single scoop of water.