I work at an office computer that is not associated with my iCloud account and where I cannot install Mac App Store apps, and I don't like having to type text into my iPhone when I'm at a keyboard. I have come up with various solutions in the past. I wrote Taskpusher in PHP, which uses URL schemes to send info to apps on your iPhone using Pushover. I've written a command line Unix script for Pushover as well. Recently, I've been using Pushbullet a lot, so I figured I'd make use of their API to create a reminder on my iPhone using Fantastical 2.
This web app will let you write a reminder in natural language in the browser, and send a push notification to your phone. When you open the notification and tap "open link," a reminder will be saved in Fantastical.
I've also written a companion web app that will get you all the device IDs associated with your Pushbullet account, provided you enter your Access Token.