Question about PocketBook InkPad Color 3

There is none, but you can use Dropbox and have all your books there over Wi-Fi instead of internal memory, but 32 GB in EPUB and even PDF is a lot of storage I have uploaded about 40 Epubs and have only used around 600 MB of Memory( around 15 MB per book)

There are no external connections for memory cards, only USB C for charging or connecting to a PC. However, the internal memory of 32GB (of which approx. 28GB is free) is large enough for ebooks.

No, it does not. Only the charging cable connection.