iniviting family to usa to attend wedding

[sunny4all]

hi , i am getting married to usa citizen, i am an indian citizen on h1b visa , my inlaws are happy to sponsor my parents and sisters to attend wedding in usa .
i understand they all need visitors visa

what all documents do my inlaws( sponsors) need to send to my family?
what documents do my family need to provide for the visa ?
are there any one in the same situation as me in this forum ?
can any help me
thanks bye