To edit existing attributes, go to STORES > Attributes> Product and select an attribute from the list.To create a new attribute,click Add New Attribute button.There are many types of attributes which you can create,one of the most useful is a dropdown attribute which lets you define a list of values that will be available when creating new products.
Important:
After making any changes in the attributes and AttributeSets,you may need to reindex the data in your Magento (3.2 Index management)and flush the cache (3.1 Caching system).
Let's see an example of a dropdown attribute manufacturer which stores a list of product brands.Fill in the form as follows: