Like many of Adobe's mobile apps, Adobe Post requires (at least) a free Adobe account, and you have to be signed in to use it. After signing in, you're presented with the Remix screen, design presets to get you started.
Overall, I like the interface. I do have a few quibbles, though. Adobe groups the designs by category, which doesn't always make much sense; there's a big difference between these different type of lifestyle posts, though "food" and "travel" work a little better. The last group is Exclusive, which has designs with more sophisticated typography and additional fonts; you unlock it by sending an email to someone. (I explain that later in this slideshow).
Rather than merging into the other categories when you unlock these designs, it remains a separate group, which I don't like. The fonts also go into an Exclusive group in the font list, when they really should be merged into the classifications.
The remix process is easy and straightforward. You can change everything in the post. Here, I started by replacing the stock photo with one of my own. (I'll get to that hash tag overlay later.) You choose images via the little photo icon on the top of the screen -- the Photo option brings up filters.
When you double tap on the text block you can choose a different font, decoration treatment, and type/background color pairs which are automatically suggested based on color palettes pulled from the image. Post doesn't have a huge choice of fonts, but it's got some nice ones and Adobe plans to add more over time.
Shapes and colors
Once of the really neat things about the app is that Adobe leverages its Color (nee Kuler) technology to pull multiple palettes of complementary colors from the photo. Tapping on the current palette cycles through the choices for the text. You can also choose the text background shape, drop shadow or add a social media icon. Resizing the shape resizes the text. I wish there were a font increase/decrease size option as well.
You can always reapply a different design if your choices have gotten away from you, or apply a filter. The dynamic filters are limited, but it's an intelligent selection.
The app saves your posts as editable. You can also duplicate them if you don't want to mess up the original. And you can share from this screen as well.
Other sources of images
If you don't like the stock photos in the supplied designs, you can take a photo; pull photos from your Photos; grab from Lightroom or Creative Cloud; or search through a public domain image library.
How do I unlock thee?
You can get rid of that product hash tag and unlock the additional designs by allowing the app to email an ad for it to someone. Thankfully, you only have to do it once, and you don't have to do it publicly. (For instance, I just sent it to one of my dummy email addresses.)
On the left is the tweet it wants you to send to unlock the exclusive content when you use the share buttons on the previous screen. I have a private Twitter account with zero followers that I can post to so I don't spam people with these false endorsements, but if you don't, I'd insert the text "Sorry, Adobe is making me spam you with this tweet to unlock content" before posting. At least you only have to do it once. More irritating, when posting to your accounts, it also automatically inserts its own hash tag. You can delete it, but you have to delete it every time. At the very least, it should turn that off if you're a Creative Cloud subscriber, because you've already paid for that convenience a billion times over. If not, Your best bet is to save the finished graphic to your Photos and then share from there.