i have a pdf book and i want to creat an app from this book
You might be able to do this with your pdf: https://puravidaapps.com/snippets.php#2pdf
Pdf files are inherently large so you might have to convert your pdf to an html file or to plain text and reduce its size by a significant amount. If your book does not contain a lot of pictures, an html or plain text version might be a reasonable way to present your book as an App Inventor application (eBook).
What you do depends on what your book contains : text exclusively, text plus images. If it contains images, the images can be made to a smaller file size.
To make an eBook using text files or html files , the advice here might be helpful: eBook
or Taifun’s
Regards,
Steve
Or, if you really want to have some AI2 fun:
https://sites.google.com/view/metricrat-ai2/guides/view-any-pdf-in-webviewer