The package is registered in the General registry so it is easily installed by

import Pkg; Pkg.add("OhMyREPL")

Automatically start with Julia.

One way of automatically starting the package with Julia is by putting

atreplinit() do repl
        @eval using OhMyREPL
    catch e
        @warn "error while importing OhMyREPL" e

in your .julia/config/startup.jl file. Create this file (and directory) if it is not already there.

You can also compile OhMyREPL into the Julia system image. This will mean that there is no need to edit your .juliarc file and the Julia REPL will start a bit quicker since it does not have to parse and compile the package when it is loaded. The way to do this is by using