Q:

Where to place the word "easily"?

Where should I place the word easily — before or after edit and share your bookmarks? 

Do you want to edit and share your bookmarks easily?

or

Do you want to easily edit and share your bookmarks?

Context: Promotion text or a kind of slogan for an online service.

A:

Your second sentence is was missing the particle to, which is needed. So there are in fact three choices:

Do you want to edit and share your bookmarks easily?
Do you want to easily edit and share your bookmarks?
Do you want easily to edit and share your bookmarks?

(1) and (2) are easily understood, although there are those who don't like split infinitives where to is separated from edit, so that one might be a second choice.
(3) is the pedant's version and best avoided altogether; if you say it, it's fairly easy to make easily to edit into a single phrase (so it's not want easily). However, it's not obvious when reading it.
Put easily at the end, where it will apply to both bookmark operations, be understandable and create a fluid sentence. [Edit: Just what's required for an advertising leader question.]

