The paper presents a study of the Bianchi type-I space–time model with perfect fluid in f(R, T) modified theory of gravity, where R is the Ricci scalar, and T denotes the trace of the energy–momentum tensor. The gravitational field equations of f(R,T) are solved using expansion anisotropy as a suitable function of the average scale factor. Besides, we estimate the best-fit values of the model parameters by using the combined dataset of Cosmic Chronometers (CC) consisting of 31 measurements, the type Ia supernova dataset composed of 1048 measurements and the Baryon Acoustic Oscillations dataset consisting of ten measures with the Markov Chain Monte Carlo (MCMC) method. The resulting deceleration parameter shows that the Universe initially decelerated and later achieved an accelerated phase. Moreover, the paper analyses the cosmographic and cosmological parameters, suggest some improvements and illustrates findings through diagrams.