The usual line is that you are making a derivative work of all three libraries. When you distribute that, each individual component library must be redistributed under its original licence. The resulting derivative work - the whole product - must be distributed under a licence that honours them all.
Since one of the components is AGPL3, the resulting product must be distributed under a licence which is at least as permissive as the GPL - such a licence is referred to as being GPL-compatible. The FSF maintains a list of such licences, and Apache 2.0, the MIT X11 licence, and the MIT Expat licence (you do not say to which you refer) are compatible.
So as I understand it - and remember I am not a lawyer, and even if I were, I'm not your lawyer - you must release each component under its original licence, and the combined work under any one of the three (or, if you want to complicate matters, any other AGPL3-compatible licence).
You also ask
am i able to sell my app?
Yes, of course; free software may be sold, and often is. But you may not deprive your users of the four freedoms; in brief, you must provide them with the source code, and the rights to use it.
am i able to make in app purchases to donate to me?
Yes, you may; but you may not prevent other people from removing or altering that code.
As much i know the biggest problem would be the AGPL license. I use
the library to create PDF files (iText). How should it be handled?
I don't entirely understand this part of the question.
Or can i make some features paid, but not that one, which are from the
AGPL licensed library?
You may certainly charge for features, but when you distribute them to paying users, you must include full source, and the rights to use it, so that users may redistribute them if they wish.
Finally, I should add that not everyone agrees that linking your code to another's library makes a derivative work. You should get advice on this question, because if it doesn't, everything I wrote except the second sentence is false. However, most people that I know do not take this position; that is, they accept that linking creates a derivative work, and thus that such a derivative will be bound by all the licences on its components.