We all have documents sent to our phones. I mean, when you have some giant form sent to you in PDF, you don't want to have to keep it open for days while you look at it! Here's a super helpful hint if you want to save PDF's to read later.
So when we open our email, we should find the PDF in a little box. If you click on it, it'll open it inside the Mail application. That's not exactly what we want. So instead of tapping it, we're going to tap and HOLD it. It will give you a menu that should say, "Quick Look" and "Open in...".
Now, before we go farther, we need to download iBooks. This is a free app by Apple specifically made for reading stuff (hence the name, iBooks). When we have that downloaded, it will now show, along with "Quick Look" and "Open in...", "Open in iBooks". Now, when we press on the the new option, it will show our book in iBooks.
So maybe you already had iBooks and even had a couple downloaded. You'll notice that your old books are no longer there. No worries! All you have to do is is simply press on the "Collections" button in the top left-hand corner and select "Books". If you want to get back to your PDFs, simply press it again and instead, tap "PDFs". Congradulations! You have now saved your first PDF to iBooks.