Route::delete('caption/{id}', 'DetailController@deleteCaption');

public function deleteCaption(Request $request, $id) {
    $caption = Caption::findOrFail($id);
    $caption->delete(); //doesn't delete permanently
}

<form action="caption/{{$caption->id}}" method="delete">
    <p value='{{$caption->id}}'>{{$caption->content}}</p>
    <button type="submit">Delete caption</button>
    <button type="submit" formaction="/">Accept caption</button>
</form>