The MicroBooNE experiment uses a liquid argon time projection chamber (LArTPC) located at Fermilab, Chicago. MicroBooNE is able to detect neutrinos from two accelerators: on-axis from the Booster Neutrino Beam (BNB) and off-axis from the Neutrinos at the Main Injector (NuMI). While one of the primary objectives of the MicroBooNE experiment is to search for short-baseline neutrino oscillations using the BNB, it also has a rich program of R&D, neutrino-argon cross section measurements and beyond the standard model searches. This thesis presents a detailed study of the off-axis neutrino flux from the NuMI beam at MicroBooNE as well as measurements of the charged current flux-averaged total and differential electron neutrino and antineutrino cross section on argon using this beam. The data used in these measurements was taken during the first year of MicroBooNE running while the NuMI beam was in forward horn current mode. These are the first high statistics measurements of electron neutrino argon interactions and include the first measurement of this cross section as a function of the outgoing electron energy and with full angular coverage. The measurement is compared to the GENIE and NuWro generators and shows consistency with both.