Creating custom Wordpress theme involves several steps:
Setting up a development environment: This includes installing a local server, such as XAMPP or WAMP, and installing WordPress on it.
Choosing a starter theme: It is a good practice to use a starter theme as a base for your custom theme. You can use a popular starter theme like Underscores or use a framework like Genesis.
Designing your theme: Use design software such as Adobe Photoshop or Illustrator to create a design for your theme, including layouts, colors, and typography.
Coding your theme: Write the HTML, CSS, and PHP code to bring your design to life. You can use a code editor like Sublime Text or Atom to write the code.
Adding functionality: Use WordPress functions and template tags to add functionality to your theme, such as menus, widgets, and sidebars.
Testing and debugging: Test your theme on different devices and browsers to ensure it works correctly. Use tools like Firebug or Chrome Developer Tools to debug any issues.
Deploying the theme: Once your theme is complete, you can export it as a zip file and upload it to your WordPress site.
Customizing and maintaining the theme: Customize the theme according to user needs and maintain regularly for better performance and security.
Keep in mind that creating a custom WordPress theme can be a complex process, especially if you are new to WordPress development. It is recommended to gain some experience with HTML, CSS, PHP and WordPress development before starting to create a custom theme.