Fic titles on AO3 are very different than those on Wattpad. (And yes, works on AO3 are commonly referred to as "fics", not "books".)
Just give your fanfic a regular title.
There is zero need to mention the fandom or primary ship/genre in the title of the work. AO3 has specific tag fields for that.
If a fic is part of a series, there is zero need to mention the name of the fanfic series or order in that series within the title. That is what the "Order Series" function on a series is for.
AO3 users see a title that has "Character x Character", "Character x Reader", or "Boys Love" (or whatever) in parentheses as extra information that can easily be found in the relationship tags or additional tags field, they will automatically know you came over from Wattpad. They will also be less inclined to click on your fic.
YOU ARE READING
A Wattpad User's Guide to AO3
DiversosTutorial/Guide for Wattpad users who are migrating to AO3, have never used it before, and/or are unfamiliar with the culture/etiquette on AO3. Written by a Fandom Old who has been using the Archive of Our Own since 2011.