A common problem with beginners to WordPress after they create a new site is that they are unable to add anything to their custom menu. In some cases, there are just no options to choose from to add to the menu, in others there is just a vague heading saying, “no items” as well as numerous other problems. here are the steps you should take to resolve any of those issues.
1. While in the custom menu screen (Appearance -> Menus), click “Screen Options” in the top right.
2. Check everything in the top row, including “categories,” “links,” “pages,” etc.
Without these checked, there are no lists of pages to be added to your menu and the page will appear blank. I’m not sure why they would ever be unchecked, but for some reason, in some WordPress installations, they default to that.
Create a Menu
You must create a menu before some options are actually available. So if you haven’t created one already, create a new one and save, and all the other options should become available to you. If you are finding that boxes are greyed out and unavailable to you, odds are that this is your problem.
Newest version of WordPress
It helps to have the most recent version of WordPress in these instances as well. Some of these features started out not very user-friendly, and over the years have become a lot easier to use. I would recommend maintaining the newest version of WordPress whenever a new one becomes available. remember to backup your files and database before updating!
Hopefully these will solve your problem! Let me know in the comments.