Obtaining　reasonable　geometric　and　electronic　structures　of　excited　states　is　essential　for　accurately　predicting　the　thermally　activated　delayed　fluorescence　(TADF)　for　the　application　in　organic　light-emitting　diodes　(OLEDs).　Both　electronic　and　geometric　factors　are　evaluated　using　density　functionals　for　reproducing　the　vertical　emission　(E-VE(S-1))　and　singlet-triplet　splitting　energies　(Delta　E-ST)　of　28　typical　TADF　molecules.　It　is　found　that　most　TADF　molecules　(charge-transfer　type)　can　easily　twist　upon　excitation,　indicating　the　importance　of　constructing　a　rigid　molecular　structure　for　improving　the　performance　of　TADF　OLEDs.　Functionals　with　insufficient　exact　exchange　will　result　in　the　substantial　underestimation　of　the　relaxation　energy　of　T-1,　suggesting　that　the　hybrid　functionals　such　as　B3LYP　should　not　be　used.　Overall,　the　best　approach　for　calculating　E-VE(S-1)　and　Delta　E-ST　is　the　descriptor-tuned　LC-omega　PBELOL　functional　combining　the　CAM-B3LYP-optimized　excited-state　geometries,　which　shows　mean　absolute　deviations　of　0.21　and　0.10　eV,　respectively.