Group tabs in Safari on Mac
You can organize tabs into groups that make it easy to quickly switch between groups of related websites.
Create a Tab Group from the tabs in the current window
In the Safari app
on your Mac, click the down arrow 
next to the Sidebar button in the toolbar.If the sidebar is open, click the Add Tab Group button
in the toolbar.Choose New Tab Group with [number] Tabs.
Enter a name for the Tab Group, then press Return.
Create a Tab Group by selecting tabs
In the Safari app
on your Mac, click the down arrow next to the Sidebar button in the toolbar.If the sidebar is open, click the Add Tab Group button
in the toolbar.Choose New Empty Tab Group.
Enter a name for the Tab Group, then press Return.
Control-click a tab in the tab bar, choose Move to Tab Group, then choose the Tab Group.
You can also drag tabs from the tab bar into a Tab Group.
Open a Tab Group
In the Safari app
on your Mac, click the down arrow next to the Sidebar button in the toolbar.Choose a Tab Group.
If the sidebar is open, click a Tab Group in the sidebar.
To preview thumbnails of the websites in a Tab Group, Control-click the Tab Group in the sidebar, then choose Show Tab Overview.
You can mail the links in a Tab Group to others by dragging the Tab Group from the sidebar of Safari to a mail message.
Tab Groups are shared with your iPhone, iPad, and any other Mac signed in with the same Apple ID.