A client want me to create an excelfile for him which includes office script.
How can I do that without being part of the client's organization?
(scripts can't be shared with external accounts and I don't want to host excelfile and script anyway)
Is is possible to create some kind of package (Excelfile + script) the client can "install" in his organization's office365?
Will it work if the client just put the script file in his "Office-Script" folder?
Yes, just send the person the script in an email, you can find the script in your personal OneDrive in this following location ...
... they just need to then copy it to their personal OneDrive and it will appear in Excel.