In Safari on Mac, saving a tab as a new bookmark is as easy as selecting Bookmarks -> Add Bookmark... from the menu bar. In iOS, the option is a little more hidden, but once you know where it is, it's just as easy to use.
- In Safari, navigate to the website you want to save as a bookmark.
- Touch and hold the Bookmarks icon at the bottom of the screen.
- Tap Add Bookmark.
- Give the bookmark a title, and tap the icon under Location to select the folder where you want to save it.
- Tap Save when you're done.