Android，EditText通过新活动保存

How can I preserve data between activities? For instance, I have an edit text and a button in Activity A. I fill in that editText and then click on the button. That button starts a new intent, Activity B. In B there are several buttons, but all of them if clicked on, start activity A again. I want that editText to be still filled in as well as pass specific data to Activity A depending on the button pressed in Activity B. I know this has to do with onStop() -> onStart(), but couldn't get it to work.How can I preserve data between activities? For