This is how I would suggest playing the chords:
Bb (bar E shape on 6th fret)
Ab (bar E shape on 4th fret)
Eb (bar A shape on 6th fret)
Ebm (bar Am shape on 6th fret)
Gb (bar E shape on 2nd fret)
D
[Seulgi] Sometimes you gotta be bold
Just rock the world
Boo-yah!
Bb Ab Eb Bb
[All] Lalala lalala lalala la (happiness!)
Bb Ab Eb Bb
Lalala lalala lalala la
[Irene] Are you happy? uh!
Bb
[Seulgi] Gomineun go up
Ab
Kkulkkulhan gibun change up
Ebm
Himeul naeryeogo ije wind up
Ab
Han bange meotjin iri gadeuk straight up
Bb
[Irene] Nan maeil deo Style up
Ab
Gimun up doeneun ire jipjung
Ebm Ab
[Wendy] Naega haengbokhage saneun bigyeoreul jom malhae bolkka
Bb
[Joy] Achine nan jameul kkae
Eommakke saranghandago malhae
([Irene] Eohyuchakhan nae ttara)
Bb
[Wendy] Joljol nareul ttaraon happyga
Neomu gwiyeowoseo haengbokhae
([Irene] Uh yaega malhandae)
Bb
[Seulgi] Ireon money jeoreon power
Ab
Geugeotman tta, tta, tta, ttaragada
Gb
[Irene] Eoreundeuri jjanhae boyeo
Ab
Geudeureun jeongmal haengbokhaji anha
Bb
[Joy] Gippeun iri meotjin iri
Ab
Segyeneun cham, cham, cham, manheun dera
Gb
[Wendy] Geureon money Geureon power
Ebm
Urineun gwansimdo kkeunheobeorin ji orae
Bb
[Irene] Dalla dalla naneun jom
Ab
Haebogo sipeun geunyang hago malji
Gb
Gomin gomin hadaga
Ab
Eoreuni doemyeon huhoe manheul tende
Bb
[Joy] Eoje oneul naeildo
Ab
Haengbogeul chatneun naui moheom ilgi
Gb
Dalla dalla naneun jom
Ebm
Geungjeongui himeul naneun mitgo itji
Bb Ab Eb Bb
[All] Lalala lalala lalala la (happiness!)
Bb Ab Eb Bb
Lalala lalala lalala la (nan wonhae!)
Bb Ab Eb Bb
Lalala lalala lalala la (kkumkkuja!)
Bb Ab Eb Bb
Lalala lalala lalala la
[Irene] Are you happy? uh!
Bb
[Joy] Hakgyo ganeun gire mannan chingu naege dallyeowaseo
Ab
Paljjang kkigo useojuni Joko
Ebm
[Irene] Kkirikkiri moyeo jangnanchideon napjaaedeul
Gb
Naega jinagani uisikhaeseo Joko
Bb
[Wendy] Jansori hajiman
Ab
Sesangeseo naega jeil jotan eomma
Ebm Gb
Hey hey tv soge ssaumbakke moreuneun eoreundeul ppae
Bb Ab
[Seulgi] Jeomjeom deo joheun gyeol
Eb Gb
Nan naraseo haengbokhae
Bb Ab
Deo gibun joheun geon
Eb Gb
Nae gyeote neo itdan geo
[Irene] Uh what you wanna be?
Bb
[Joy] Ireon money jeoreon power
Ab
Geugeotman tta, tta, tta, ttaragada
Gb
[Irene] Eoreundeuri jjanhae boyeo
Ab
Geudeureun jeongmal haengbokhaji anha
Bb
[Seulgi] Gippeun iri meotjin iri
Ab
Segyeneun cham, cham, cham, manheun dera
Gb
[Wendy] Geureon money Geureon power
Ebm
Urineun gwansimdo kkeunheobeorin ji orae
Bb Ab
[Joy] Dalla dalla naneun jom haebogo sipeun geunyang hago malji
Gb
Gomin gomin hadaga
Ab
Eoreuni doemyeon huhoe manheul tende
Bb
[Irene] Eoje oneul naeildo
([Wendy] Jeomjeom deo joheun gyeol)
Ab
Haengbogeul chatneun naui moheom ilgi
Gb
Dalla dalla naneun jom
([Wendy] Nan naraseo haengbokhae)
Ebm
Geungjeongui himeul naneun mitgo itji
Bb Ab Eb Bb
[All] Lalala lalala lalala la (happiness!)
Bb Ab Eb Bb
Lalala lalala lalala la (nan wonhae!)
Bb Ab Eb Bb
Lalala lalala lalala la (kkumkkuja!)
Bb Ab Eb Bb
Lalala lalala lalala la
[Irene] Are you happy? uh!
Bb
[Wendy] Shine on me
Ab
Let it shine on me
Gb
Nae pume
Ebm
Let it shine
Bb
Shine on me
Ab
Let it shine on me
Gb
Nae du pare
Ebm
Let it shine
Bb Ab Eb Bb
[All] Lalala lalala lalala la (happiness!)
Bb Ab Eb Bb
Lalala lalala lalala la (nan wonhae!)
Bb Ab Eb Bb
Lalala lalala lalala la (kkumkkuja!)
Bb Ab Eb Bb
Lalala lalala lalala la
Happiness!