Hide a Cache with Cachly
Caches can only be created and submitted on geocaching.com. Currently there is no mobile app that allows creating and submitting new geocaches.
However, if you are interested in hiding your own geocache, Cachly has tools that can be helpful in making your hide. Tap your current location and then tap the ... button. From there you can choose Create Offline Geocache. This will bring up a new screen allow you to choose an offline list to save the geocache. Next you will see the Add Cache screen where you can enter information about the cache that you want to create, along with the coordinates.
Once you have the information saved in Cachly you can visit the Hide a geocache page to create your new hide.