TOPIC:

Good afternoon I have a question, is possible to add text on the pdf in the same way as an image or a line, I would like to leave blanks to be filled with text

It is not clear what you mean, but you can add text and place it where you want using PageContent.TextMove, PageContent.TextNextLinefor an example, check PDFTestAct.gen_form1

Hello I mean the following:

I would like to add text over a pdf, I have a book in pdf which contains some questions that I want to answer through the application

Step 1: select the writing tool
Step 2: write the answer
Step 3: move it text if necessary, rearrange or remove it

Is it possible to do this?
I do not find something similar in demos

This can be achieved using Editbox annotation, that can be added using Page.AddAnnotEditbox
Repositioned using Annotation.SetRect
Removed using Annotation.RemoveFromPage
For more details, you can check How to add an Edit Text annotation (Android)

Hello how can I run the PDFReader activity , appears as deprecated

Yes, PDFReader is deprecated. We recommend to use RDPDFReader instead (PDFLayout instead of PDFReader) as it's better performance wise.
You need to run the RDPDFReader module (com.radaee.reader.PDFViewAct)