The Office apps that you install on your PC or Mac such as Word, Excel, PowerPoint and Outlook are available to you when you are not online.
With OneDrive in Microsoft 365, you get file storage that you can access when offline. When you make changes while offline, they will be sync’d to OneDrive and across the rest of your devices when you reconnect.
With Outlook, you can read emails already delivered to your inbox or draft new emails and meeting requests. Your inbox and outbox will sync across the rest of your devices when you reconnect.

Subscribers can install Office apps on up to five PCs or Macs, five tablets, and five mobile devices. You can count hybrid Windows devices, such as the Microsoft Surface Pro, as either a PC or a tablet.

Microsoft 365 Home apps can be installed on up to six PCs or Macs, and six tablets. Microsoft 365 Personal, which is relatively a newer option, offers access to the same apps and storage space as Microsoft 365 Home, except you can only install it on one PC or Mac, and one tablet or iPad.

Devices Microsoft 365 work on Works across PC, Mac and mobile on both iOS and Android operating systems.