Add Google Custom Search to your blog easy as one-two-three, copy and paste these Custom Search Element code into your site’s HTML.
For WordPress:
WordPress control panel > Widgets (Under Appearance) > Add new (Text Widget) > paste the code into the box (You can label it according to your wants) > click Save Changes. Congrats! you’re done.
For Blogger/Blogspot:
Blogger Dashboard > Layout > Add Gadget > HTML/Javascript > paste the code into the box (You can label it according to your wants) > click Save.
Or
Blogger Dashboard > Layout > Add Gadget > Search Box > Save.

That’s it! you’re done.