This app was mentioned in
with an average of
Not legally. Not for free. Which means you either have to pay or be satisfied with whatever scraps you can find.
Marvel has a subscription service/app that lets you browse their archives. There is another one for other brands and indies. Great to use on a 10-inch tablet.
There are others, too, but I'm not really familiar with any of it enough to recommend anything else
Make sure you downloaded the "Marvel Unlimited" app, not the regular app. Marvel used to have their own branded Comixology storefront. (I'm not sure if they still do.)
Looks like the Android app was also updated
If you're logged on Marvel.com here's the page with all the Marvel comics you can read.
Keep in mind Marvel Unlimited updates with the latest comics six months after they're released. So say Spider-Gwen #1 released in January. It wouldn't be available until July.
Here's the link to the Marvel Unlimited app.
This is the app you need for Marvel Unlimited. Not just the regular Marvel Comics app. If you're using a Kindle Fire or something you need to side-load the APK. Google is your friend there.