How would you read text from a custom GUI?

Good evening you guys.
I'm trying to make a custom GUI where you can enter a text and click send.
Is it possible to somehow alter the inventory type ANVIL to remove the item slots on the bottom?
(It is an enum so I can't override it as usual)
Or should I use a lectern (how do i get the text from a lectern? And how can I let the player type into it?)
Or is there perhaps another way of entering Strings that doesn't involve commands (so it feels nicer and it's more intuitive)
(I'm thinking maybe a regular custom inventory where you select each letter individually)
Thanks for your help ^^

 

I believe the only things that accept text input from players are anvils and chat and you can't remove parts of a GUI without mods, so no.

EDIT: Nvm I'm dumb, I forgot books existed in the game. I don't think you are interested in sign input because I believe there's a 16 character limit on each line.

 

Okay thanks I'll try to do that

 

I think you can do signs, but I don't know how to do it.

 

Signs, as well as books, are possibilities.

 

@MagicZerda There is a library you can use for signs:
Sign GUI - Use the sign interface to get user input | Bukkit Forums
Maybe try and use the Anvil GUI and have the player click an item in the GUI that opens up the Sign GUI, then get the input from the sign once you click done.

Holy that's a lot of GUI's I put in there lol