After trying many different proceess, apps, websites and approaches, the following route seems to be the most natural, as most musicans have a email account and know how to steer it.
a) An email is sent to you with some hilerous bants and a link to your music.
b) Click to the link and be taken to your file or folder containg your music.
c) Download your file/s.
NB You can listen, i.e. 'stream', straight from the email browser but this will play at a low quality as it is 'streaming'... It is always best to download files for critical listening :)
Upon completion of your project, WhatStudio will deliver to you the finished stereo file/s, meeting current audio conventions and/or in any file format you request.
Any multi-tracks or stems of the session this must be discussed and/or arranged within the session time, or risk additional charges. See 'Can we get the STEMS' for more info.