This tutorial shows how to create custom options in Magento 2.x.
Open the admin panel and go to Products – Catalog section to open the product.
Navigate to the Advanced Settings – Custom options and click on theAdd New Option.
Set a title and specify an input type. You can select "Required" in case customer must select one of the options (it is enabled by default).
Click on Add New Row.
Specify a new title, price, price type and SKU (SKU field is not required). You can add the additional fields using Add one more row button. We have added three rows.
You can add one more option using the Add New Option link.
We have selected a text field as an Input type. Such option will not be required in our case. Save changes
Check the product details page. We have added custom options.
Feel free to check the detailed video tutorial below: