禁止使用者調整視窗尺寸大小的方式：

root.resizable(False,False)

例子：

from tkinter import *
from tkinter import ttk
import csv
from tkinter import messagebox

root = Tk()
root.geometry('400x300')
root.wm_title('資訊錄入')
root.resizable(False,False)

Label(root,text='資訊錄入',font=('楷體',20),bg='gray',fg='white').pack()
ttk.Separator(root,orient='horizontal').pack(fill='x')

f = Frame(root)
f.pack()

Label(f,text='姓名').grid(row=0,column=0)
name = Entry(f)
name.grid(row=0,column=1)

Label(f,text='身份證號').grid(row=1,column=0)
uid = Entry(f)
uid.grid(row=1,column=1)

Label(f,text='職業').grid(row=2,column=0)
job = Entry(f)
job.grid(row=2,column=1)

Label(f,text='手機號').grid(row=3,column=0)
phone = Entry(f)
phone.grid(row=3,column=1)

Label(f,text='備註').grid(row=4,column=0)
description = Entry(f)
description.grid(row=4,column=1)

def tj():

    name1 = name.get()
    uid1 = uid.get()
    job1 = job.get()
    phone1 = phone.get()
    description1 = description.get()

    file = open(f'{name1}.csv',mode='w',encoding='utf-8')
    csv_writer = csv.writer(file)
    csv_writer.writerow([name1,uid1,job1,phone1,description1])
    file.close()

    messagebox.showinfo('提示','儲存成功')


def close():

    root.destroy()


ttk.Button(f,text='提交',command=tj).grid(row=5,column=0)

ttk.Button(f,text='關閉',command=close).grid(row=5,column=1)


root.mainloop()