Make a wordpress post from an iOS app

new iOS developer here. I'm looking to build an app that uses a Wordpress database to populate a news feed, and I've found a good amount of info about grabbing posts from Wordpress but nothing about posting FROM the app TO the database. I know that the code can't be written here, but I was hoping someone knew where I could find how to do this or point me in the right direction. Thanks in advance for any advice!