It s a must to disable “find my iphone” first?

It is compulsory to disable find my iphone before reset and erase all content? Because I want to give my ex phone to someone.

after erase it, told me to set a new iphone, I set it manually, and indeed, everything was erased. On settings and app store it wasn’t my apple ID anymore. Should I worry about “find my iphone”, if was disabled or not?