So use A lot of apps to edit so I may as well give them to you

Aviary and picsart: I use it to blend, fix blurry images, crop, put borders and use filters » Both Free

Superimpose: it's like computer photoshop but it's quite good » $6.49 Australian dollars

Magic hour: I use it for filters. I make my own and I download some, it's really easy to use » two versions, lite: comes with adds, certain amount of filters allowed to be downloaded and I don't think you can make filters. Paid: Unlimited filters downloaded, you can make filters and comes without adds. » paid version: $1-2 Australian dollars

Pixlr: exactly like Picsart and Aviary » Free

Phonto: best text app that comes with out watermark in bottom corners. You can also download fonts, which I do quite often. They also have pretty good add ons » free

Adobe draw: I use this for outlining people/drawings for certain covers

Layout: mirroring images » free

Photo layers: it's like superimpose but instead of merging images you can move them around to how you want it, I prefer this over superimpose. » $1.49 Australian dollars

Wattpad covers: for cropping images to the size of wattpad's cover (if it makes any sense » Free

Photoshop mix: I haven't tried this out yet but apparently you can do photoshop and filters ETC » Free, comes with Add ons

Ps Express: I haven't tried this out either but it is used mainly for making pictures professional looking photos, it's all filters » free, comes with add ons

Picplaypost: I use this for most my collages, it's very good as you can also put a watermark on the picture if you're using it for other than Wattpad covers