Show shared company calendar on mobile device

I am moving a client from Gmail Business to Office 365 Exchange.

I am trying to figure out the best method to have a shared company calendar show up on their mobile devices.

I can create a dedicated mailbox to host the calendar, which they can add to their device as a separate account.  I am pretty sure this will work but the customer will have to pay for another mailbox every month.

I could also create a Public Folder calendar but I don't know if they can view it on a mobile device.  This would save the cost of a dedicated mailbox.

Perhaps there is even another method that I am unaware of.

What would you do to accomplish this task?

Thank you in advance!