If you are unable to upload files, it could be because the developers of the app only allow uppercase file extensions at least on the devices I tested. The only files it let's me upload are for example filename.PES with pes in uppercase. So you can fix this by renaming the files like this, then it works. Intern developers it seems, the instructions even use lowercase, I wonder if they user tested the app at all...
The file was already a pes file. I did not convert it. I just put it into the cloud and accessed it from my cloud drive. But you could also put the design on a USB and use an adaptor to acess the USB from your iPad or Android tablet/phone
