According to Wikipedia “Third Person Of Singular is a grammatical category of pronouns and verbs used when referring to objects or individuals other than the speaker or his addressee(s)”.  As far as I’m concerned, the 3 Person Of Singular is the form of a verb used with singular nouns and with the pronouns he, she, and it.

Third Person Of Singular general rules:
the third person singular the verb always ends in -s:
I want—-> He wants.
I need—-> She needs.
I give—-> He gives.
I think—-> She thinks . 
Negative and question forms use DOES (=the third person of the auxiliary’DO’) + the infinitive of the verb: He wants. Does he want? He does not want.

Third Person Of Singular exceptions rules:

Verbs ending in -Y preceeded by a vowel :
-y +s: I play—-> He/She/It  plays, I pray—-> He/She/It  prays.
Verbs ending in -Y preceeded by a consonant :
-y +ies: I fly—–> He/She/It flies, I cry—-> He/She/It cries. 

Verbs ending in -X -SS -CH -SH:

 -x, -ss, -sh, -ch+es: He/She/It passes, He/She/It  catches,
 He/She/It  fixes, He/She/It pushes
Verbs ending in -O :
 -o +es: He/She/It goes, He/She/It  does.