Welcome to SimpleSigning! This website has the philosophy of keeping things simple for legacy iOS devices. This part of SimpleBit handles signing any IPAs that you have (using our own/your collection of enterprise certs). We would NOT accept AppleID or Ad-hoc certificates that require UDID to be signed into the app.
This method is in beta, and things may not work. (its in development, what do you think?) have a wonderful day!!