We run a small business, and the managers would like to have the calendars on their phones synced with each other so that they know what is going on with the other. Most of them are using iphone and one is using an android phone. Is there a calendar app that we can use. Any information is appreciated.
You have several options:
Your first option is to use a "third-party" app that works for both iPhone and Android. For example:
Your other option is to use a shared calendar in a service such as Gmail. I personally think this solution is better. You have two options: either setup an arbitrary email account that all the managers use to sync their calendar to, such as [your-company-calendar]@gmail.com, or, you create a calendar, and if all the managers have their own Gmail accounts, make them all owners of it. This allows you to use the default, built in, calendar app on both Android and iOS devices.
To set this up (I am generalizing the steps that work with both setups):
This should allow them to look up, and create events from the default calendar app on the devices.
Shared Calenders work between Android and Iphone using Gmail on both phones. See these instructions Shared Calendar: