  We present the first measurement of the single-differential $\nu_e +
\bar{\nu}_e$ charged-current inclusive cross sections on argon in electron or
positron energy and in electron or positron scattering cosine over the full
angular range. Data were collected using the MicroBooNE liquid argon time
projection chamber located off-axis from the Fermilab Neutrinos at the Main
Injector beam over an exposure of $2.0\times10^{20}$ protons on target. The
signal definition includes a 60 MeV threshold on the $\nu_e$ or $\bar{\nu}_e$
energy and a 120 MeV threshold on the electron or positron energy. The measured
total and differential cross sections are found to be in agreement with the
GENIE, NuWro, and GiBUU neutrino generators.
