what do you think your life have been changed by IT?用 by 还是 with？

IT是多余的,have应改为has.
用by.
可改为: By what do you think your life has been changed? 或主动态
What do you think have (has) changed your life?如果你想象what是几件事用have一件用has.
意思: 你认为你的生活是被什么改变的? 或
你认为是什么改变了你的生活?

with

By.时态没错

用with,句子应该是what do you think your life had been changed with IT?

应该是by,have been changed 表示被动
用with的话句子应改成 What do you think your life have changed with IT?