I see this question pop up a lot, and the best advice I can give is to just buy the ebook. Trying to find a safe, free PDF of 'Ignite Me' is honestly more trouble than it's worth. You'll end up clicking through sketchy links and worrying about viruses more than you'd be reading. The book isn't that expensive on Amazon Kindle, Apple Books, or Google Play Books, and you know you're getting a clean file and actually supporting the author, Tahereh Mafi. It feels different when you've legitimately purchased a story, like you've properly entered the world instead of sneaking in a back door.
Public libraries are your absolute best friend here, too. Apps like Libby or Hoopla let you borrow the ebook or even the audiobook for free with a library card. The waitlists can be long for popular titles, but you can place a hold and it'll just show up on your device when it's ready. It's completely safe, legal, and you're not risking your computer's health. I borrowed it that way the first time and ended up loving the series so much I bought the physical box set later.