I've been trying to add magical items to a character sheet but some, such as blackrazor, aren't showing up in the add equipment menu. I have double checked that everything is enabled and I have searched without any filters but it simply just won't show up when I searched. I've read that a lot of people have had this issue and I'm curious if anyone knows how to solve it.

Blackrazor is not free content, it is only available from the DMG. If you do not have access to the content from the DMG, either through purchase or Content Sharing, then you will not have access to the magic items from that book including Blackrazor. If you should have access to the DMG, then follow this link and double check that your Account Entitlements are in sync: (https://www.dndbeyond.com/account/marketplace).

If that doesn’t solve your dilemma then please refer to the FAQ for other potential fixes: (https://www.dndbeyond.com/forums/d-d-beyond-general/bugs-support/142100-how-to-access-content-on-d-d-beyond-faq).

I hope that helps.

Thank you so much, I thought I had already purchased it because I could search its contents but I now realize I still need to buy it.

It must be being shared with you in another campaign.