while...: #your loop
button = pygame.Rect(cordX, cordY, width, height) #your bytton
pygame.draw.rect(win, (0, 0, 0), button) #show button
mx, my = pygame.mouse.get_pos() #mouse pos
if button.collidepoint((mx, my)): #cheak if mouse on button
if pygame.mouse.get_pressed()[0]: #cheak if mouse is preesed
# writh here what you want to happend
pygame.display.update()