I've recently added Moodle Mobile support to my site, to support some blended learning courses I've been teaching. It's been a great success and I can see attendees doing quizzes while commuting, etc.
My existing Moodle site provides updated lecture slides by embedding PDF's, which I've noticed requires the PDF be downloaded and then viewed in the Android (in my own case) PDF viewer.
I'm researching whether there are better options. I also use Google Slides and have experimented with embedding a Google Slides presentation into a test course - which worked well on the web, but the slides, which are embedded into a note on the course page, do not seem to be reachable on the app. Is this perhaps because they're on the course page? The text-only note above them appears just fine.
What other applications are you using to make lecture slides available?