How to save checkbox with array checkbox?

I have a checkbox with name of currently_studying. But I did not successfully.

foreach ($request->field as $key => $value) {
    $educational = new Educational;
    $educational->user_id = auth()->id();
    $educational->grade_id = $request->grade_id[$key];
    $educational->field = $request->field[$key];
    $educational->institution_id = $request->institution_id[$key];
    $educational->branch = $request->branch[$key];
    $educational->institution_education = $request->institution_education[$key];
    $educational->gpa = $request->gpa[$key];
    $educational->country_id = $request->country_id[$key];
    $educational->state_id = $request->state_id[$key];
    $educational->city_id = $request->city_id[$key];
    $educational->state_name = $request->state_name[$key];
    $educational->city_name = $request->city_name[$key];
    $educational->entrance = $request->entrance[$key];
    $educational->graduate = $request->graduate[$key];
    $educational->currently_studying = $request->has('currently_studying')[$key];
    $educational->save();
}