Yes it does work non-natively on an iPad i.e. on safari browser of iPad. We are yet to achieve mobile support, the current version is primarily a web app. And

Yes it does work non-natively on an iPad i.e. on safari browser of iPad. We are yet to achieve mobile support, the current version is primarily a web app. And yes, it is possible to send letters to users who are not on @bubbles yet. You can mention email id of the recipient(s) on the letter itself and it will be delivered as PDF over email. With your signature and drawings everything. :)