Are you just starting out digital art? Well look no further! Here are 3 of the best apps I have found (ok one really isn't that great unless if it's your only option/ you have premium) listed from my favorite to my least favorite!

Autodesk sketchbook: this app is really nice. It's got a wonderful layout, and is very aesthetically pleasing. It allows up to 64 layers, and has several sets of brushes. It has a time lapse recorder, but you may have to google how to do it if you can't find out.
I use this one, and I also know that UltimateFanWing does too (and if you've even seen ONE of her pieces you KNOW HOW GOOD SHE IS—)
Compatible with: iOS, Android

IbisPaint X: extremely similar to Autodesk, allowing multiple layers and brushes. Some of the brushes are locked (you can buy them), but if you watch a video, all are free to use for a little while. If you have all brushes, there are more than Autodesk. This is also widely used for anime artists, so it has a variety of shading things (they are complicated though). Plus, if you like speed paints, it has an easily done speed painting thing. This is what most people use.
Compatible with: iOS, Android

Artflow: ok I don't even want to get started on this one. I've had really bad experiences with this app, but if you have a kindle, this is your best option (unless you look up how to get the google play store on your kindle)! It allows you to undo 7 times only, and you have 2 layers available at a time. There is a weird version of the lasso that I never learned how to properly use, and a very small selection of brushes. With premium though, you have access to more brushes, more layers, and infinite undos. But this is also something that Autodesk has for free. Also, I heard from my friend Brindleshine that if you get premium it's actually pretty decent! She uses it for her art, and also does a wonderful job, so at least that goes to show it can work!
Compatible with: iOS, Android, Amazon (Kindles)

Most people use Ibis, and some use Autodesk, like myself. Really, it's just a matter of preference. I would Test out both of them, and use Artflow as a last resort. I personally prefer Autodesk sketchbook because of the layout. It is nice, neat, and organized. It's super easy to use, but the lasso tool may take a bit of researching to quite understand. You can also have an account to save all of your work to other devices!

I hope this helped! It will also be in my art book just so y'all know ;3