Adding custom HTML code or Google Analytics or webmaster verification code in wordpress site is simple. You just need to install a script editor plugin which allow you to add custom code inside header and footer code of your wordpress website.
Plugin that I used : Head and Footer Script Inserter
Plugin URL: https://wordpress.org/plugins/header-...
Read article on "How to add custom code in wordpres site header & footer?"
Article URL: http://www.thakurblogger.com/how-to-a...