I don't know whether there is such an app - I use evernote and am very very happy with it. I use it on my telephone and laptop. I take pictures of my spread with my telephone and send them to Evernote where I can write down my interpretation.
I have a Tarot notebook in Evernote where I collect all my tarot stuff, with folders for decks, spreads, readings, card meanings and special stuff (numerology, astrology, kabbalah). I collect material from websites, good AT articles, book summaries and journal entries I wrote myself. Evernote is searchable and flexible. It does freeze on me from time to time, but that's the only problem. Great app for tarot aficionados, I feel.
(But I'm far from being an expert ... at my advanced age...)
I added a screenshot to show how I use Evernote. The screenshot is from my laptop but as I said, I use Evernote on my telephone, too.
Notes can be exported in different formats but not .pdf. Probably it's possible to convert them to pdf but I don't know how. But pf can be added to Evernote with ease.