Should screen readers read the content without tab or with tab?

I am designing a web application, which can be accessed by any visually impaired person. This web application contains various pages, and each page can have paragraphs with links, form input fields, collapsible sections and buttons.

When my user opens the page, should screen readers read the content on my page automatically, element by element, from top to bottom?

Or, should users take control by using tab key and navigating through the page, having the screen reader read the content where the cursor focus is?