Greetings AchyutChaudhary,
We understand you have some questions about features of Safari.
Bookmarks are saving a link that you want to revisit or may visit frequently. Favorites are a category of bookmark and by placing them in the favorites you can then opt to have them in a bar across the top of Safari for even easier access.
A reading list is also a list of webpages, but ones you want to read and then close, not necessarily revisit. Also, with the Reading List you can read it offline as well.
Here’s more information:
Bookmark webpages that you want to revisit in Safari on Mac
Add webpages to a Reading List
Thanks.