Hi, welcome to Android Forums.
It depends entirely on the browser you are using. I use HTC One stock browser, Dolphin, Chrome and Opera Mini, and they all have a slightly different procedure.
HTC stock - tap menu (three dots right hand side of address bar or longpress menu button), then tap + at the top right of the options list.
Chrome - tap menu, action page opens with a star top right, tap the star.
Dolphin - tap the + at the left hand side of the address bar.
Opera Mini - tap the Opera logo right hand side of menu bar, tap bookmarks, tap add at the top of option list.
All the above actions will let you save the current web address as a bookmark/favourite. You have some options like entering a name.
There is a sort of common approach in the four procedures, hopefully enough to help you if you use another browser. If not then please resubmit and include your browser/s name/s and someone is sure to help.
Even better, why not register as a member for an interactive response.
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