The other versions weren't completely accurate, so I made this. 
Chords used:
G:      3 2 0 0 3 3
D/F#:   2 x 0 2 3 3
Em      x 2 2 0 0 0
C:      x 3 2 0 1 0
D:      x x 0 2 3 2
F:      1 3 3 2 1 1
Am:     x 0 2 2 1 0
If you'd like you can alternate by playing Em as Em7 and C as Cadd9 in the verses.  
Em7:    x 2 2 0 3 3  
Cadd9:  x 3 2 0 3 3
Standard tuning
Capo 7th fret
VERSE:
G                        D/F#
       You walk into the room
               Em
So perfect but unaware
          C
Making me stop and stare
      G                          D/F#
Every time I heard he broke your heart
           Em
Can I just fix you girl?
           C
Show you a different world?
PRE-CHORUS:
D                 Em
    I'll take you anywhere
C                     G
    I'll put you on a throne
D                    Em
    I'll lay down my heart, I swear
         F                              D (one strum)
And I'll make sure that you'll never be alone
CHORUS:
G       D/F#   Am
Only my shadow knows
      C
How I feel about you
G       D/F#   Am
Only my shadow goes
        C
Where I dream of you and me
Em       D     C      
Should I go or wait
         G          Am
Is it too soon, too late
C (one strum)  G
Only my shadow knows
VERSE:
G                            D/F#
     I've been loving you so long
               Em
And now that I got the chance
https://www.coveralia.com/acordes/shadow--acoustic--austin-mahone.php
          C                     G
I see you need to dance on your own
                     D/F#
So I'll wait another day
       Em
Maybe another year
          C
I'm gonna be right here, oh
PRE-CHORUS:
D                 Em
    I'll take you anywhere
C                     G
    I'll put you on a throne
D                    Em
    I'll lay down my heart, I swear
         F                              D (one strum)
And I'll make sure that you'll never be alone (alone)
CHORUS:
G       D/F#   Am
Only my shadow knows
      C
How I feel about you
G       D/F#   Am
Only my shadow goes
        C
Where I dream of you and me
Em       D     C      
Should I go or wait
         G          Am
Is it too soon, too late
C              Em 
Only my shadow knows
BRIDGE:
               D
I wish I could say all these words
          C                            Em
All these things that your heart never heard, yeah
Em            D                        C (one strum)
But I saw the pain in your eyes and it sealed my lips
CHORUS: (play 2 times)
G       D/F#   Am
Only my shadow knows
      C
How I feel about you
G      D/F#    Am
Only my shadow goes
        C
Where I dream of you and me
Em       D     C      
Should I go or wait?
         G          Am
Is it too soon, too late?
C (one strum)  G (repeat chorus)
Only my shadow knows