1)Before knowing effect of Moon In 3rd house we have to know about Moon and Third House. So you may read this
Queen Of Planet Moon—
Third House Power house of your horoscop——
2)Third House belongs to younger siblings,Strength,short travel,communication.Moon belongs to respect,travel,imaginations,etc.
3)Strength—Third House belongs to physical strength and brain strength so Moon In 3rd house indicating Native may be good physical strength and stout body construction. But as Moon is female planet so native don’t like physical work out. Native like comfort Life style.Moon In 3rd house native may be courageous.Moon is belongs to changabe so there brain strength is not fixable type they are fickle in brain strength.Afflicted moon here is good for mental strength.
4)Siblings—Moon is female planet so native younger siblings may be sister(Genraly siblings who born after native).Good moon is indicating Younger siblings may get success, may be happy,success in bussiness,may be earn good wealth. Native may get respect from siblings or native respect siblings.Native may takecare of his siblings.
5)Communication—As moon is not good for communication because moon feels difficulties to getting in touch with any one so moon In 3rd native may be speaking less.
Moon belongs to imaginations so native have good imaginations power or simply native have good imaginations strength. So Moon In 3rd house is good for any imaginations work.
4)Travel—Third house belongs to short travel and Moon is a planet of Travel so native may like travel. And native may be doing any work where a lot of Travel is necessary or doing a continuous travel a regular time interval or may be travel a lot.
5)3rd house is 12th from 4th house and Moon is Karak of Mother so an afflicted Moon indicating problem regarding mother or not good for mother.
6)Moon In 3rd also indicating native may be sexy in nature because 3rd house is 1st karam house .
7)Moon In 3rd house indicating native may get success in bussiness. Native may have changabe bussiness or jobs.
8)3rd house Moon is indicating native may fickle minded regarding religious activity or some time he like some time in denial mode regarding religious work.