Hello Aspirant!

You can try following links for studying free e books online in Telugu :

http://www.gutenberg.org/browse/languages/te

http://www.teluguthesis.com/p/blog-page_20.html

https://www.telugubooks.in/

https://www.scribd.com/doc/234901725/List-of-Telugu-Books-Free-Download

https://kinige.com/

Hope it helps !