[On behalf of ILD and CEPC Collaborations] Future e+e- colliders offer excellent possibilities for precision studies in the Higgs sector due to the clean experimental conditions and low backgrounds compared to hadron colliders. At lower energies i.e. below 500 GeV, the Higgstrahlung is the dominant Higgs production mechanism. With the recoil mass analysis technique being the unique feature of e+e- colliders, the Higgstrahlung allows model-independent studies of the Higgs couplings as well as the access to the invisible Higgs decays. If considered simultaneously with WW-fusion dominating Higgs production at higher energies, determination of the Higgs total width is possible at a percent level. Scalar sector searches are reviewed for ILC and CEPC using recent research updates obtained with the fully simulated ILD and ILD-like detector for CEPC.