what is a 'submission'

what is considered a 'monthly submission'? the free allows 100. Is this how many times you can fill out a form? Can we save forms direct to the device, and can we share via e-mail directly?

A submission happens when a customer/user submits the form. For the free user, 100 submission is its limit per month.

You can check it here:Understanding-Your-Account-Usage-and-Limits

I'm not sure I understood your questions correctly,do forms submissions be saved to a mobile device and can submissions be shared via e-mail?

Forms can be saved as a pdf which can be saved in any mobile device.

Here is a guide on how to create a pdf form : How-to-Create-a-PDF-Form

while submissions can be sent through email and autoresponder.

Here are some guides that can help you : Explanation-of-Email-Notification-and-Autoresponder-Settings

Setting-up-an-Autoresponder-Email

I hope this information helps you.