The product categories in the eCommerce stores help the customers to easily find the products that they are looking for. Magento 2 allows the merchants to categorize their products into different categories and sub-categories. If you are a Magento 2 store owner selling a few products on your store, you can easily classify the products into different categories from the backend admin panel. But what if there are thousands of products that you want to classify? It can be a daunting task to do that manually from the backend admin panel. In such cases, you may require to programmatically assign products to multiple categories in Magento 2. I have prepared a programmatic way to assign the products to multiple categories using category IDs and product SKUs.