\documentclass[12pt]{article}
\usepackage{ifxetex}
\RequireXeTeX
\usepackage{fontspec}
%xetex-itrans - to convert ITRANS to unicode devanagari
\newcommand\isan{
	\catcode`\^=11
           \catcode`\~=11
           \fontspec[Script=Devanagari,Language=Sanskrit,Mapping=itrans-sdvn]{Siddhanta}
           } 
\newcommand\gu{\catcode`\^=11
            \catcode`\~=11
           \fontspec[Script=Gujarati,Mapping=itrans-sguj]{Shruti}
           }
\obeylines
 
\begin{document}

{\isan
\bigskip
OM shrii gaNeshaaya namaH 
\bigskip
Daa.cO Qdhaatu Q dhaatu Q sup Q naaman ekaO dviO bahuO
\bigskip
charitaM raghunAthasya shatakoTi pravistaram .
ekaikamakSharaM pu.nsAM mahApAtakanAshanam .. 1..
dhyAtvA nIlotpalashyAmaM rAmaM rAjIvalochanam .
jAnakIlakShmaNopetaM jaTAmukuTama.nDitam .. 2..
sAsitUNadhanurbANapANiM nakta.ncharAntakam .
svalIlayA jagatrAtuM AvirbhUtaM ajaM vibhum .. 3..
\bigskip
1 2 3 4 5 6 7 8 9 10 100 1000
\bigskip
ka kaa kA ki kii kI ku kuu kU ka.c ke kai kA.c ko kau kaM kaH ka.N 
\bigskip
a     aa / A       i      ii / I       u     uu / U 
RRi / R^i    RRI / R^I    LLi / L^i    LLI / L^I
a.c     e      ai     aa.c / A.c   o     au     aM / a.n   a.N   aH
\bigskip
k.h ka.h m.h ma.h
k     kh     g     gh     ~N / N^
c / ch    chh / Ch     j     jh     ~n / JN
T     Th     D     Dh     N
t     th     d     dh     n
p     ph     b     bh     m
y     r      l     v / w
sh    Sh     s     h      L / ld
x / kSh     GY / j~n / dny     shr
\bigskip
ka     kha     ga     gha     ~Na / N^a
cha    Cha     ja     jha     ~na / JNa
Ta     Tha     Da     Dha     Na
ta     tha     da     dha     na
pa     pha     ba     bha     ma
ya     ra      la     va / wa
sha    Sha     sa     ha      La / lda
xa / kSha  tra   GYa / j~na / dnya     shra
qa Ka Ga fa Ja za 
\bigskip
ka kaa ki kii ku kuu qa 
sa saa si sii su suu
khRRi khe khai khaM khaH kha.c kha.N 
De Dai DaM DaH Da.c Da.N
lda gRRi gR^i rga 
a.c aa.c a.ckTa 
aa.cfis fa.ckTa kaa.cla kol fA.cla 
Da.N OM AUM om  U.N
raamam raamaM raama.n raama.N 
raama.c raamam.h raamau raamaaH

raama , raama . raama - raama ! (raama) 'raama'
''raama'' raama : raama ; raama: raama: raama ?

raam.h raam raama
}

\end{document}