I just started using this platform with my players and I am setting up all of their character sheets, however whenever adding Items I can't add items from all the books I own. I own all the content on D&D beyond but one of my characters who has blackrazor can't equip it. I have all of the boxes unchecked I just can't get it to appear? 

Could you post here the link address of your player's character sheet? Moderators can take a look.

This is the one

Do you have the sharing enabled?

How can I tell? He doesnt have any of the books which is why I am creating the characters but he has access to all the other content, classes, races and spells.

I just tried doing it for one of my own characters but it still doesn't appear.

In order to share purchased content with your players, you or one of your players needs a Master Tier subscription and enable the sharing on the campaign page.

As your own character has the same problem, can you access this page or died it directed you to the marketplace?

https://www.dndbeyond.com/magic-items/blackrazor

Ahh I needed to subscribe. It was a problem cause it was in another campaign I think but I just subscribed and everything works now. 

Thanks for your time Filcat

I've had a similar problem.   Have the DMG purchased, have sharing enabled, but when I search for Blackrazor in the character sheet, it does not come up?  What am I missing?