Author: Aidil Ikbar

TextEdit on Mac supports tabbed windows, allowing you to manage multiple documents within a single window. To enable and use tabs in TextEdit:

1. Show the Tab Bar:
   • Open TextEdit.
   • Go to the View menu and select Show Tab Bar.
2. Create a New Tab:
   • Click the + button in the tab bar to open a new tab.
3. Merge Existing Windows into Tabs:
   • With multiple TextEdit windows open, go to the Window menu and choose Merge All Windows to combine them into a single window with tabs.

This feature is available in macOS Sierra and later versions.  

For a system-wide setting to prefer tabs across all applications that support them:

1. Open System Preferences.
2. Go to the Dock preferences.
3. Find the option Prefer tabs when opening documents and set it to Always.  

This adjustment will encourage apps to use tabs instead of separate windows when opening new documents.

Source: https://osxdaily.com/2017/01/24/using-textedit-tabs-on-mac/