The online exchange of data preferably takes place via my OneDrive account. This is more secure than the transfer via e-mail and there is no restriction regarding the amount of data compared to many e-mail accounts.
Especially concerning projects or whenever files have to be handled by more persons, Trello and MS Teams are convenient tools for the collaboration, as well for exchanging files.
All data will be handled strictly confidential and I guarantee highest discretion. Should it be necessary to hire subcontractors due to a high work load, those underlie the same conditions as myself via a contract.