Matter-wave Atomic Gradiometer Interferometric Sensor (MAGIS) will be the largest vertical atom interferometry experiment, under construction at Fermilab. It consists of three 10 m atom interferometers across a 100-meter baseline. MAGIS will search for ultralight dark matter, test quantum mechanics in new regimes and serve as a technology demonstrator. The MAGIS-100 experiment is an intermediate step towards a future kilometre-scale experiment, potentially sensitive to gravitational waves in the previously unexplored mid-frequency band. A phase shear imaging is going to be employed in MAGIS-100. This novel imaging technique relies on the precise control of the retro-reflection mirror to imprint spatial fringes across the cloud of atoms by tilting the mirror at the final interferometry pulse. These fringes can be used to extract the interferometry phase. The high precision adjustments of the mirror are achieved by a combination of PZT and linear actuators, and the development of this system is going to be presented here.