You can visit libretexts.org to search their robust OER collections. On this site, mouse over Explore the Libraries at the top and then click on the Discipline you're interested in.
There is also a search box at the top, once you open a discipline library, where you can enter keywords to search across the bookshelves, campus bookshelves, and learning objects.
When you open the curated Bookshelves, those resources will be divided into separate bookshelves by topic area. You can click on a title to open it.
As shown above, you can find the Creative Commons license at the top-right underneath the book title. Then there is usually a description of the book and a list of book pages and chapters. At the top-right are tools to get the PDF and download the book. To share the book, you can just use the URL in the browser address bar.
One of the primary needs is sharing OERs with your students. You can use the URL in the address bar to link to the OER within your course syllabus or content, but you can also export these titles in order to import them directly into Canvas. You do not need an account for this. You can do this by opening the desired title and going to Download.
Mouse over Downloads at the top-right (shown above), then click on Import into LMS. This will download a file type that you can import directly into Canvas.
Once you have it downloaded, open Canvas and go into settings on the left-side of the course pane. Go to 'Import Course Content' on the right side of the course pane. Set the Content Type as "Common Cartridge 1.x Package". For course, select the .imscc file that you downloaded. Select "All Content" and click import.