how to do key after laravel code example

Example 1: laravel foreign key

Schema::table('posts', function (Blueprint $table) {
    $table->unsignedBigInteger('user_id');

    $table->foreign('user_id')->references('id')->on('users');
});
OR
Schema::table('posts', function (Blueprint $table) {
    $table->foreignId('user_id')->constrained();
});

Example 2: laravel drop foreign column

// Searched, laravel drop foreign column
Schema::table('users', function (Blueprint $table) {
    $table->dropColumn(['votes', 'avatar', 'location']);
});