Perhaps Header is the first place visitors look at when they go to your site. The first impression is always important; therefore, if the Header can convey your message to users, that is very great! The simple message given to them can be an understandable and clear menu or an amazing and eye-catching design of the header or diversified header styles of your site also make the most choosy customers feel satisfied.
In the most essential respect, a header should contain 2 parts which are menu area and logo
Here is structure of sections in Header, which will help you to acquire essential knowledge of building a Header. In terms of an striking and personal Header, I suppose that it depends on your creativity:))
Set up Menu
Customize Header

As for Hermosa theme, you will need to create 2 menus called Main Menu Left and Main Menu Right. To create a menu, for example Main Menu Left, you will follow these steps:
Step 1: Navigate to Appearance–> Menu section of your admin sidebar.
Step 2: Click the Create A New Menu link to make a new menu. Enter the name, Main Menu Left then click the Create Menu.
Step 3: To add menu item, select one of your created pages on the left hand side and click the Add To Menu button. You can also add different posts from the left side.
Step 4: To add a custom menu item, enter a custom name and link into the Links box.
Step 5: Manage your menus by using the drag and drop functionality. To create a dropdown menu in Menu Structure, simply drag a menu item on the left side to the area on the right side.
Step 6: After setting up your menu, scroll down to the bottom of the page to assign the menu on the Theme Location box. Choose  Primary Menu Left
Step 7: Once It’s all done, make sure you click  Save Menu.

Similarly, you can also create Right Menu and choose Primary Menu Right in Step 6

Now returning to the site, you will see the menu shown on the header like this:

Yet when you see the header on our demo site:

You can wonder yourself “why is the header of my site different from that of your site?”.To achieve such design, refer to this link:

Customizer _ Header