If you are looking for a method to download e-books for free without downloading any applications. Then here's the solution.
So, let's get it into the work.
STEP 01:
First open the pdfdrive.com website. The interface will look like this.

STEP 02:
Now in the search bar type the name of the book that you need to download.

STEP 03:
Now in the search result select the book that you need to download

STEP 04:
Here click on the Download button or else you can preview the book using the Preview button.

STEP 05:
Now wait few seconds until it checks the file health.

STEP 06:
Now click on the Download (PDF) button. That's it, now the download will begin. You can also change the format using the dropdown.
