AutoConnect automatically turns on the wifi connection of your device for a brief period of time at a set interval.
By doing so, you can still get your mails, notifications, and so on but without draining your battery by having wifi constantly turned on.
Also useful if your data plan is expensive. Simply turn it off and let AutoConnect use wifi while saving your battery. Same if you don't have a data plan.
AutoConnect also features a scheduler so that you can restrict the auto connection times.
Note: this is mostly for older phones. Recent phones (after 2015) have optimized wifi connections with powersaving options.
Check the website for the complete documentation and support.