The menu panel that appears at the top of the portfolio shows categories, other categories, and the search box. Just for a reference below is the screenshot for menu panel.
If you wish to hide this panel you would need to update some settings.
From the WordPress dashboard navigate to Portfolio > Settings. Settings listed for Display manage the menu for the portfolio.
You can disable all the fields for Display.
Disabling above settings will not display menu bar for default shortcode – wp_portfolio
If you want to display menu bar for the particular portfolio you can add attributes to the shortcode. – wp_portfolio show-categories="yes" show-other-categories="yes" show-search="yes"
Note: Shortcode has priority than settings. Shortcode will overwrite the Display settings.
Read more about WP Portfolio ShortCode and Attributes.
How to Hide Portfolio Menu Panel?
How to Hide Portfolio Menu Panel?