Best reader

I just got an android phone but I can't find out how to download and read my books. I can view in the kindle app but not bookmark. is there a good app to read and bookmark pdf on android or am I just stupid

Why pdf? Aren't digital comics more common as zip/rar/cbz/cbr files? I used Perfect Viewer on Android, now I use Bubble. The first has more features, the latter is quite bare-bones but does its job.

EDIT
Just noticed PV! has a pdf plugin.

Thanks for your help I have been looking for a way to add all my books and this app helps.

As mentioned above, generally speaking the ZIP downloads are recommended - they are a much better fit for comics than PDF. And Perfect Viewer is a decent reader for Android.

Thanks everyone I know have a reader for my phone.