Can MOPS be configured so that mobile printing only works within our network?
Yes, by default MOPS has no need to be connected to the Internet. Everything runs locally.
But you can change this if you decide that external users shall be able to print via upload or email.
Does MOPS save documents or filed in a public cloud?
No. All documents and files are saved locally within your Network. In case you want to offer external email printing by means of a public email address the emails will be stored only for a very short time at your email provider until they are fetched by MOPS (usually 3-5 seconds)