How to I add a search bar to my headers and navigation?

Hi, I find it hard to add a search bar to my headers. I've already created a HTML for my search bar, I've added it in the HTML section.

<div class="search">

<form action="http://mywebsite123.forumotion.co.uk">
<input type="text" name="search" placeholder="Search for..." /> <input type="submit" value="Search for" />
</form>

</div>

I don't know how to make it appear on the header

Are you using the default search engine?

nevermind solved it myself