Laravel Relationships with pivot table

Hi all, I have a made 3 migration tables "Customers", "Products", "Invoices" with a pivot table, and not sure if i understand the workings behind the relationships correctly, if one has 2 columns with related data then a pivot table should be created then one would reference the pivot tables by foreignId , like 2022_12_19_100107_create_invoice_product_table.php,

I just want to share my code just to know if I do understand it correctly or if there might be something I'm doing wrong, any advise and guidance will be appreciated

This is the Customers table

	Schema::create('customers', function (Blueprint $table) {
        $table->id();
        $table->unsignedBigInteger('products_id')
            ->references('id')
            ->on('products')
            ->onDelete('cascade')
            ->comment('reference to products');

        $table->unsignedInteger('created_by_admin_user_id');
        $table->foreign('created_by_admin_user_id')
            ->references('id')
            ->on('admin_users')
            ->onDelete('cascade');

        $table->string('company');
        $table->string('name');
        $table->string('email');
        $table->string('contact');
        $table->string('address');
        $table->string('company_reg');
        $table->string('vat_no');
        $table->boolean('enabled')->default(false);
        $table->timestamps();
    });

This is the products table

		Schema::create('products', function (Blueprint $table) {
        $table->id();
        $table->unsignedInteger('customers_id')
            ->references('id')
            ->on('customers')
            ->onDelete('cascade')
            ->comment('references to customers');

        $table->foreignId('customers')
            ->references('id')
            ->on('customers')
            ->onDelete('cascade');

        $table->unsignedInteger('created_by_admin_user_id');
        $table->foreign('created_by_admin_user_id')
            ->references('id')
            ->on('admin_users')
            ->onDelete('cascade');

        $table->string('product_name');
        $table->string('description');
        $table->string('brand');
        $table->string('catagory');
        $table->string('unit_price');
        $table->timestamps();
    });

this is the invoices table

		Schema::create('invoices', function (Blueprint $table) {
        $table->id();
        $table->unsignedBigInteger('customers_id');
        $table->unsignedBigInteger('products_id');
        $table->unsignedInteger('created_by_admin_user_id');
        $table->foreign('created_by_admin_user_id')
            ->references('id')
            ->on('admin_users')
            ->onDelete('cascade');

        $table->date('published_at')->nullable();
        $table->date('due_date')->nullable();
        $table->string('payment_type')->default('EFT');
        $table->boolean('paid')->default(false);
        $table->string('tax');
        $table->string('subtotal');

        $table->timestamps();
    });

This is the pivot table

		Schema::create('invoice_product', function (Blueprint $table) {
        $table->id();
        $table->foreignId('products_id')
            ->references('id')
            ->on('products')
            ->comment('reference to products');

        $table->foreignId('invoices_id')
            ->references('id')
            ->on('invoices')
            ->comment('reference to invoices');

        $table->foreignId('customers_id')
            ->references('id')
            ->on('customers')
            ->comment('reference to customers');

        $table->timestamps();
    });