I am looking at my email, and when it asks me to view it in the browser, I get this annoying little sidebar, which the print is way too small to read. I don’t know how I got this little sidebar thing, but I cannot get rid of it can you help?

Are you triggering a preview window (these cannot be resized) or a slide-over view?

When opening a link, a long-touch will usually open a small preview window - along with an Action Menu - whereas a “tap” will open the link.

You may find these overview Apple video guides to be helpful:

After viewing, you’ll be ready for the additional Multitasking Guide:

Use Multitasking on your iPad - Apple Support

The iPad User Guide for iPadOS is also a rich source of information. Here are links to both the downloadable and online versions of the Guide:

‎iPad User Guide on Apple Books

iPad User Guide - Apple Support

I hope this explanation and additional information is helpful in resolving any difficulties you may be having with Multitasking features of your iPad.