You can import files like PDF, EPUB, text, Markdown, and Word into the Reading List. You can pick files from locations available on your iPhone, such as iCloud Drive or Dropbox.
Open the Files import menu
On the Reading List, tap the Import button (cloud icon).
Tap Files.
Pick files
The file picker opens. Select the files you want to import. You can select multiple files at once.
Import complete
Selected files are added to the Reading List as text.
Supported file types
PDF (.pdf), EPUB (.epub), text (.txt), Markdown (.md / .markdown), and Word (.docx) are supported.
Legacy Word format (.doc) is not supported.