Microsoft Outlook is Microsoft's email and calendar service. It keeps email, calendars, contacts and to-do lists in one place, with apps for desktop, mobile and the web. The Outlook app can also show accounts from other mail services, such as Gmail, Yahoo! and iCloud, next to Outlook.com and work or school accounts.
Outlook scans attachments and links for threats, can encrypt messages so that they cannot be forwarded, and removes clutter with its Focused Inbox and Sweep features. Copilot, Microsoft's AI assistant, drafts emails and summarizes long threads. Other programs reach Outlook data through Microsoft Graph, Microsoft's API (an interface that another program calls over the internet): an app can filter, search and sort messages in a mailbox, send messages, set up Inbox rules that move incoming mail to folders, and read a user's categories, contacts and calendar, for consumer and for organization accounts.
A basic Outlook account with 15 GB of mailbox storage is free. Paid Microsoft 365 subscriptions, billed monthly or yearly, remove ads and add storage and other apps.