Inbox by Gmail has received a lot of updates these past few weeks, from opening up to the public even without invites, to improving on the control options on the mobile app, to having a new Trip Bundle specifically for your travels. Now, you also have newer and probably more efficient ways of adding to your reminders. And yes, if you didn't know it yet, or you're just new to Inbox, the app does have a reminders section that you can use for productivity purposes.
One of the new ways with which to add items to your reminders on Inbox is for when you receive emails that are asking you to do something, Inbox will then suggest adding a reminder so you won't, well, forget. For example, if your boss emails you and says something like "Please schedule an appointment for me with HR on Monday". Inbox will then suggest "Add Reminder: schedule your boss' appointment, etcetc". Google uses natural language understanding technology to help figure out and recognize if it is something you would add to your to-do list.
The other way is for those who are also using Google Keep for productivity and memory-keeping. When you make a reminder to your Google Keep, whether the app or the web version, it will automatically appear in your Inbox, with a link to the Google Keep for more details. This is a good way to make sure that you really won't forget the important thing you have to do, unless you don't open either of the two.
The new features are already available in your Inbox by Gmail. If you don't have the apps yet, you can download Inbox and Google Keep for free from the Google Play Store.