With Word Online you can create numbered and bulleted lists, but you can’t sort lists alphabetically. You can sort lists alphabetically in the desktop version of Word.
If you have Word, click Edit Document > Edit in Word or click Open in Word to open your document.
Then follow the instructions in Sort text in a list alphabetically.
When you save the document and reopen it in Word Online, you’ll see the changes you made to the list.
Tip: Word Online works seamlessly with Word and other Office desktop programs, and we update it based on input like yours. For the latest feature announcements, visit the Office Web Apps blog.