How I can get text from TextBox to string value ?

How I can get text from TextBox to string value in workspace ?

It depends really. Here is the script I would use (put it in a script inside the textBox and put a string value in ReplicatedFirst then rename that to "string"):

local Box = script.Parent
local value = game.ReplicatedFirst.string

string.Value = Box.Text

If that fixes your problem let me know. Hope this works for you.