If you don’t know how to add categories in header then follow my this tutorial.
Let’s start by going to blogger.com
Add Blogger Categories in header Menu
If your google account is logged then you will see your blogs otherwise you will see login option so login your account and click on your blog title.
Your blogger dashboard page will appear in this page click on template.
The next page will show you your current template that you have installed and 2 option at the bottom of your blog screen shoot.
Click on Edit Html
In next page you will see your template html code.
Click on any where on the code and press ctrl+f to search.
You category which is already added in your blogger blog header.
Just open your blog to see what you need to search in many templates you can search menu1.
So just type your category name which is already added and press enter.
You will see your category like following html code
<li><a href=‘#‘>menu 1</a></li>
After found your category code just edit it and replace menu1 with your category name and
# with you category link so after editing your category your category html look like following.
You can also Add Blogger Categories without your site link like following html code.
By same process you can edit or Add Blogger Categories like next category is menu2 just edit it as you edit your category menu1. After editing click on save changes now visit your blog your categories are added.
If you don’t understand any step just drop your comments i will help you. Hope Now you able to Add Blogger Categories in your blog.