a) Can I use SharePoint on a Mac ?

The web browser experience for viewing SharePoint sites on Windows and Macintosh-based computers is nearly identical.
b) What web browsers and devices are recommended for use with SharePoint ?

SharePoint is optimally suited for the latest versions of Internet Explorer, Safari, Mozilla Firefox, and Google Chrome, as well as mobile browsers on various devices.
c) Does remote access to SharePoint require a VPN connection ?

SharePoint can be accessed remotely from any browser, directly from the Internet.
d) Are there any limitations when syncing SharePoint document libraries with OneDrive for Business ?

The limits can be accessed on the Microsoft OneDrive and Microsoft SharePoint sites.
e) Why can’t I upload documents to SharePoint ?

- To upload documents, you require at least contributor permissions, which can be obtained from your site administrator.
- The document is too large, as the maximum file size that can be saved to a SharePoint site is 2GB.
- The file type is not supported due to security reasons, and a list of blocked file types can be found on the Microsoft website.