When you go into the SETTINGS on your actual Chromebook, there are lots of built in accessibility features that you can turn on or off depending on your needs. Chromebooks also let you add extensions through the Chrome Web Store which also add all sorts of accessibility features to the Chromebook. This page deals more with the actual "SETTINGS" available on your Chromebook.
https://support.google.com/chromebook/answer/177893?hl=en&ref_topic=9016892
Google Docs: Changing Default Font Style in GOOGLE DOCS
How to Adjust Default STYLES, Font or Line Spacing in Google Docs
This will create a "default style" so that every time a new Google Doc is opened, it will use your preferred font, font size et cetera.
1. Create a new document or go into a current document with the formatting you want.
2. Drag your cursor through a couple of sentences that are set up the way you want them, with the font and line spacing you prefer.
3. Go to Format > Paragraph styles > Normal text.
4. Select "Update 'Normal text' to match."
5. Next, go to Format > Paragraph styles > Options.
6. Select "Save as my default styles."
Changing Overall Display:
You can default to a LARGER display on the Chromebook Screen itself, and also use a % increase adjustment for the Chromebook screen display. (Please note, this can cause issues if a student is using Co:Writer.)
Screen Magnifier
I've found the best setting for Magnification is to dock the magnifier bar at the top of the screen. Here's that section from Chromebook help...but if a student is needing this function, a touchscreen Chromebook is absolutely the best option as they can "pinch zoom" as needed. PINCH ZOOM much easier and fluid than using the docked magnifier bar.
You’ll see the magnified section in the top third of your screen. Your default screen will show underneath. To quickly magnify the top section of your screen, press Ctrl + Search + d, or follow the steps below.
Note: When you type in the bottom section of the screen, you’ll see what you’re typing at the top, just zoomed in."
Google Docs: Changing Background Color of page/dyslexia
Chromebook Touchpad/Mousepad speed
How to make the Chromebook Mouse Pointer larger
Google Docs: Voice Typing The below link has all the voice commands available to format your document while using Voice Typing (see "Step 3" ).
OK GOOGLE
Turn "OK Google" on or off
Turn "Ok Google" on or off from the settings
CALL (Communication, Access, Literacy and Learning ) Scotland
This site offers some handy visuals for apps and extensions that work on either Chromebooks, iPads, or Android devices.