Wordpress plan for editing theme pages - HTML, CSS, PHP source code
Which wordpress plan allow to customize theme pages ? I will need to edit theme's HTML, CSS and PHP source code to customize the website.
Advanced functions like theme's source code editing or installing plugins are not available for basic plans. So when you have an account on wordpress.com with free, personal or premium plan, you don't have options to do all these modifications.
You can edit theme's source code using Appearance editor, Theme editor or other application, when you have an account with Business plan.
If you have a Premium plan on Wordpress, you can modify CSS styles by adding of custom CSS to your website. You can find the feature in Design > Customize > Additional CSS.