import PySimpleGUI as sg

tab1_layout =  [
                [sg.T('This is inside tab 1')],
               ]

tab2_layout = [
                [sg.T('This is inside tab 2'), sg.In(key='in')],
              ]

layout = [
          [sg.TabGroup([[sg.Tab('Tab 1', tab1_layout), sg.Tab('Tab 2', tab2_layout)]])],
          [sg.RButton('Read')]
         ]

window = sg.Window('My window with tabs', default_element_size=(12,1)).Layout(layout)

while True:
    b, v = window.Read()
    print(b,v)
    if b is None:           # always,  always give a way out!
        break