Some people cannot e-sign documents

Hello. 90% of our doc recipients have no trouble e-signing, and the others say they cannot do it. Do the recipients need to previously have an Adobe Sign account to e-sign? If that is the case, this application would not make much sense, as we would have to know this in advance... so the convenience would be cancelled out. If the receiver needs to print and physically sign because they do not have an account, why not just send an attachment?