The problem with that is, your smartphone takes photos in jpeg or jpg format. This file format is not designed for editing purposes and doesn’t have all the data the image sensor can record. If you heavily edit a jpg file, it breaks apart very easily. The final image would look grainy and with less detail.
If you edit photos heavily, and want the best quality images, then you should start shooting DNG raw images on your mobile. You can pull up a lot of detail from these files and it won’t break apart easily comparing to jpegs.
Since RAW files contain a lot of information – everything the camera sensor recorded – the file sizes are going to be much bigger comparing to a jpg. A regular jpg file would be around 5MB while a DNG file would be around 24MB on smartphone cameras.
So for your casual shots, which you don’t intend to edit, to save space it’s better to shoot jpegs. If you are out there in the field or traveling, shooting Landscapes, i would highly recommend you shoot DNG images instead of Jpegs.
Not all smartphones currently support RAW image capture. Some OEMs, for some stupid reason, do not enable Camera Api 2 on their phones which is necessary for the apps to shoot raw images. OEMs like Huawei, OnePlus, LG, Google etc ship their devices with this enabled. Motorola, Lenovo, Xiaomi etc often do not enable them on their budget – mid range devices.
Adobe Lightroom Mobile has a free Pro Camera App built in which allows DNG shooting. There are some other free apps available as well. For editing raw images, you can use Adobe Lightroom, Photoshop Express or Snapseed to get the best results.