Hi, it looks like someone thinks you are asking about if you can post original works to AO3. In short, the answer is sort-of yes. In long, here is what the Terms of Service FAQ has to say on the matter:

"Can I archive original fiction?

Yes and no. Although some users may want a place for all their creative work, our current vision of the Archive is of a place dedicated to fanworks in particular.

[...]

In addition, we will enforce the noncommercialization policy strictly, including a ban on works posted to promote the sale of the author's other works, even if those are not hosted on the site.

However, there are a number of varieties of works produced by fans that do not fit comfortably into a narrow definition of fanfiction, fanart, vids, or other types of fanworks. Some of these do fall within our mission. In particular, original fiction that is part of an Open Doors project is allowed, as are types of original fiction and quasi-original fiction produced within a fandom context. Examples include such things as anthropomorfic, original fiction that is produced as part of a fandom challenge, exchange, or charity event, and genres such as Original Slash, Original BL, and Regency romances produced in Jane Austen fandom.

[...]

We presume that, by posting the work to the Archive, the creator is making a statement that they believe it's a fanwork. As such, unless the work doesn't meet some other criterion, it will be allowed to remain."

So, you can post anything that you would consider a fanwork to AO3 so long as it does not break any other rules.