This poster presents a measurement of the associated production of the Higgs boson ($H$) with a top quark anti-quark pair ($t\bar{t}H$) or a single top quark ($tH$) in the final state where the Higgs boson decays to a bottom quark anti-quark pair. Data from proton-proton collisions at a center-of-mass energy of 13\;TeV corresponding to an integrated luminosity of 138\;fb$^{-1}$ and collected by the CMS experiment at the CERN LHC between 2016 and 2018 are analysed. The observed inclusive $t\bar{t}H$ production rate relative to the standard model (SM) expectation is $0.33\pm0.26$, and a differential measurement as a function of the Higgs boson transverse momentum $p_T$ is also performed. An upper limit on the $tH$ production rate of 14.6 times the SM expectation is set at the 95\% confidence level, with an expectation of 19.3$^{+9.2}_{-6.0}$. Finally, constraints are set on the strength and $CP$ structure of the coupling between the Higgs boson and the top quark.