Hi, when you add some HTML,CSS codes to your Wp website you need to use wordpress hooks. It is better way to prevent theme updates. If you dont use this to modify footer’s and header’s HTML and css codes when theme gets updated your chenges will be lost. So I made a plugin for it and i also share with you how did i do this plugin and which hooks i do.
How to add code header or footer of wordpress without code?
When you install and activate this plugin you will see “Edit Footer And Header” above options.
After that you can use text editor to add codes to header and footer
After paste your code you can save.
Note : dont forget to clear cache to update page sources. Otherwise your analytics or other codes dont appear.