Create text_box with Entry for a list - tkinter Python

You should first create Entry

entry = tk.Entry(text_box)
entry.insert("end", item)

and later you could use it in

command=lambda:button_click(entry))

but it is inside for-loop and lambda doesn't copy value from entry to code button_click(entry) so it keeps only reference to entry and this entry is changing in loop - and finally all lambda has reference to the same variable which has last value. You have to use extra variable to copy object.

command=lambda x=entry:button_click(x))

Minimal working code

import tkinter as tk   # PEP8: `import *` not preferred

# --- functions --- (PEP8: lower_case_names)

def button_click(entry):
    print('ENTRY:', entry.get())

# --- main ---

out_list = ["item1", "item2", "item3", ]  # PEP8: spaces after comma

root = tk.Tk()

text_box = tk.Text(root)
text_box.pack()

for item in out_list:
    print(item)
    
    entry = tk.Entry(text_box)
    entry.insert("end", item)
    
    button = tk.Button(text_box, text="Copy Variable", command=lambda x=entry:button_click(x))
    
    text_box.window_create(text_box.index("end"), window=button)
    text_box.window_create(text_box.index("end"), window=entry)
    #text_box.window_create(text_box.index("end"), text_box.insert('end', item), window=text_box_value)
    text_box.insert("end", item)
    text_box.insert("end", '\n')  # adds text to text box

root.mainloop()

EDIT:

You could also use Frame to build own widget with Button, Entry, Label and button_click and later use this widget.

It can be simpler to add or hide widget.

import tkinter as tk   # PEP8: `import *` not preferred

# --- classes --- (PEP8: CamelCaseNames) 

class MyWidget(tk.Frame):

    def __init__(self, master, text, *args, **kwargs):
        super().__init__(master, *args, **kwargs)
               
        self.button = tk.Button(self, text="Copy Variable", command=self.button_click)
        self.button.pack(side="left")
    
        self.entry = tk.Entry(self)
        self.entry.insert("end", text)
        self.entry.pack(side="left")
        
        self.label = tk.Label(self, text=text)
        self.label.pack(side="left")
        
    def button_click(self):
        print('ENTRY:', self.entry.get())
        #self.button["text"] = self.entry.get()
    
# --- functions --- (PEP8: lower_case_names)

def copy_all_variables():
    for widget in all_widgets:
        print(widget.entry.get())
        #widget.button_copy()

def add_widget():
    item = "item" + str(len(all_widgets)+1)
    widget = MyWidget(frame_widget, text=item)
    widget.pack(fill='x')
    all_widgets.append(widget)

def remove_widget():
    if all_widgets:
        all_widgets[-1].destroy()
        del all_widgets[-1]

# --- main ---

out_list = ["item1", "item2", "item3", ]  # PEP8: spaces after comma

root = tk.Tk()

# - version 1 -

tk.Label(root, text="Text Box + window_create()", bg="#8080ff").pack(fill='x', expand=True)

text_box = tk.Text(root)
text_box.pack()

all_widgets_1 = []

for item in out_list:
    widget = MyWidget(text_box, text=item)
    text_box.window_create(text_box.index("end"), window=widget)
    text_box.insert("end", '\n')  # adds text to text box
    all_widgets_1.append(widget)

# - version 2 -

tk.Label(root, text="Frame + pack()", bg="#8080ff").pack(fill='x', expand=True)

all_widgets = []

frame_widget = tk.Frame(root)
frame_widget.pack(fill='x')

for item in out_list:
    widget = MyWidget(frame_widget, text=item)
    widget.pack(fill='x')
    all_widgets.append(widget)
   
frame_buttons = tk.Frame(root)
frame_buttons.pack()   

button_copy = tk.Button(frame_buttons, text="Copy All Variables", command=copy_all_variables)
button_copy.pack(side="left")

button_add = tk.Button(frame_buttons, text="Add Widget", command=add_widget)
button_add.pack(side="left")

button_remove = tk.Button(frame_buttons, text="Remove Widget", command=remove_widget)
button_remove.pack(side="left")

# - 

root.mainloop()

And when you put Button and Entry directly to Text then you can write text between widgets.