1- Login to your WordPress admin dashboard.
2- Under the dashboard menu, hover your mouse on Posts and then click on Categories.
Enter the following details in Add New Category:
Name: Enter your category name such as Computer.
Slug: Enter a slug name or leave this as it is.
Parent: Leave this to None or should you select a category, it will become a sub-category of your selected category and the browser will show a URL like https://www.example.com/technology/pc
Description: You can leave this as it is.
Now click on the Add New Category button.