Technically, a microphone distance of more than 6" is recommended, but the artistic element comes into the equation.So in terms of the issue of sensitivity/pickup of mouth noises or those slightest nuances of movement - with mic placement of say..overhead, 8-12"
The vocal artist must have a good command of the microphone technique. Depending on the nature of the song, it uses the proximity effect for a more intimate sound, or moves away or/and changes the angles of incidence relative to the microphone during stronger passages, can acoustically modify the equalization, sibilance, etc.
A good example of good mic mastery is @Wordsushi who often gets close to 2..3 inches and doesn't use a pop-filter for plosives.
A good vocal soloist needs less dynamic processing than an amateur.
It is good to pay a lot of attention to the positioning of the microphone in each particular case, in post-processing some problems cannot be satisfactorily fixed.