One-page site is a smart function that let the user show all of your site’s information into one page which split into multiple sections.
Step 1: Create a new page or edit an existing one.
Step 2: Click on WPBakery Page Builder at the top then choose Backend Editor.
Step 3: Click Add Element >> Choose Row
Step 4: Click Edit this Row
You now see a table like this
Choose the type of Row Stretch you want and keep rolling down
Step 5: Name the Row ID and click Save Change >> Publish or Update
Step 6: Come to Appearance >> Menus >> Create a new menu
Step 7: Find Custom Links in the left column
Step 8: Fill URL section by delete http:// and replace by #your row ID in step 4 >> check Main menu then Click Save Menu