When unsure, I recommend looking at well known open source applications that have the functionality that you wish to make. As an example Air is a well known process spawner that monitors for file changes and restarts applications on change. They implement the start and kill process like this:

func (e *Engine) killCmd(cmd *exec.Cmd) (pid int, err error) {
    pid = cmd.Process.Pid
    // https://stackoverflow.com/a/44551450
    kill := exec.Command("TASKKILL", "/T", "/F", "/PID", strconv.Itoa(pid))

    if e.config.Build.SendInterrupt {
        if err = kill.Run(); err != nil {
            return
        }
        time.Sleep(e.config.killDelay())
    }
    err = kill.Run()
    // Wait releases any resources associated with the Process.
    _, _ = cmd.Process.Wait()
    return pid, err
}

func (e *Engine) startCmd(cmd string) (*exec.Cmd, io.ReadCloser, io.ReadCloser, error) {
    var err error

    if !strings.Contains(cmd, ".exe") {
        e.runnerLog("CMD will not recognize non .exe file for execution, path: %s", cmd)
    }
    c := exec.Command("powershell", cmd)
    stderr, err := c.StderrPipe()
    if err != nil {
        return nil, nil, nil, err
    }
    stdout, err := c.StdoutPipe()
    if err != nil {
        return nil, nil, nil, err
    }

    c.Stdout = os.Stdout
    c.Stderr = os.Stderr

    err = c.Start()
    if err != nil {
        return nil, nil, nil, err
    }
    return c, stdout, stderr, err
}

You can find the repo here

They also reference another stack overflow post as to why they use this specific method.