Ebooks for reading Free?

Your local library. You need a library account first. If you don't have one - hopefully they have a plan in process for getting them while they are closed right now. Check their website (and don't forget that you may have city, county and nearby city libraries available).

Once you have an account, you register online for eMedia. Different libraries have different apps - but all of them are free to download on your phone or tablet. You can also read directly in your browser.

It's super easy to use. There's usually a limit (10 books or more) and a timeframe after which the books get sucked back to the library (probably 2-3 weeks). You can place holds on books that are not currently available. Makes bookshelves of the books you want to read. All kinds of great stuff.

Also, if you have Amazon Prime, they actually have free books available - many contemporary by known authors, not just a heap of self-published stuff. Plus classics and kids and magazines, etc. It's called Prime Reading. And if you don't own a Kindle, you can still either read in your browser or download the Kindle app to your phone or tablet. https://www.amazon.com/kindle-dbs/hz/bookshelf/pri...

Start with your local library.  Most loan ebooks in addition to physical media.  Your library's website should have info on what apps are supported and how to check out ebooks.  Also, Amazon and B&N offer plenty of free ebooks.

The Gutenberg  project offers out-of-copyright ebooks for free.

Many authors offer their books free on Kindle daily. Some are early books in a series shortly before a new addition is about to drop, others are self-published and seek to find a readership. Some are utter crap, and some are pretty good.

And of course your local library probably has thousands.