Category removal – Portfolio Category:

It looks like that text is coming from your theme.

I would create a child theme (you’ll only need style.css to start with), then copy whatever file it’s coming from (probably header.php but could be in another file, possibly single.portfolio.php) into your child theme. From there, remove the whole section of code that looks something like this:

<header class="page-header">
    <h1 class="page-title">Portfolio Category: Abstract</h1>
    <div class="taxonomy-description"><p>These works are created using photographic and digital processing techniques.</p></div>
</header>

The actual code will include some PHP that’s dynamically adding the correct category and description, but the main thing is to remove everything between <header> and </header>.