Decent into Avernus and the Shield of the hidden lord.

So my question is this, my players are getting close to finding the Shield of the hidden lord. the text info states that it will lie to the players claiming its a celestial being of good, etc etc. When I give the shield to a player and they click the link from their inventory are they able to see the text/info of the shield on their end? The text of the item says that the shield is a prison for the Pit Fiend Gargauth. Is the player who has the shield and clicks the link able to read that? I want to keep that part a secret as the book suggests.

You have a couple of options. The first is to click the ID button to make the shield unidentified. Players will only then be able to see the non-id name and non-id description of the shield. However this is somewhat temporary since the players will sooner or later identify it and be able to see all of the text.
A better method is to make a copy of the shield and remove all of the text that you do not want the players to see and put that in the treasure parcel, removing the original one. In this way you will be able to roleplay the shield if you want to.
If you read all of the text you'll see really that the players are not supposed to have the shield (or at least are supposed to give it up quite quickly after it is discovered). However players are likely to want to hold onto magic items.

I let the character ID it, and then pulled the player aside and went over how they could play there character based on the details given.

Oh i didn't know i could do that, Thanks Zacchaeus !