PDF files can't be uploaded directly at this moment.
You can upload the contents through covert PDFs into pictures instead.
We are currently preparing to enable direct uploading of PDF files.
HTML files can be uploaded directly.
-How to upload PDF files
1. Convert format of the PDF into PNG or JPEG, and save it.
2. Upload the picture file(PDF/JPEG) from Cards Edit page.
-How to upload HTML files
1. Select "Source" on Cards Edit page.
2. As the text box is switched into HTML Edit mode, you can enter codes in it.
3. When you completed with entering codes, select "Source" again to finish the HTML Edit mode.
4. Select "Save".
*The contents will be shown on App like this below.