This is from apples website and explains their great accessibility tool which comes as standard (FREE) with apples products, it works really well with Google Chrome

Control accessibility options with your keyboard and Siri

You can use these keyboard shortcuts to control accessibility options, or ask Siri to perform these functions. For example, ask Siri to ”Turn VoiceOver On”.

Display Accessibility OptionsOption-Command-F5
or triple-press Touch ID (power button) on supported models1
Turn VoiceOver on or off2Command-F5 or Fn-Command-F5
or hold Command and triple-press Touch ID on supported models1
Open VoiceOver Utility, if VoiceOver is turned on2Control-Option-F8 or Fn-Control-Option-F8
Turn zoom on or off3Option-Command-8
Zoom in3Option–Command–Plus sign (+)
Zoom out3Option–Command–Minus sign (-)
Invert colours4Control-Option-Command-8
Reduce contrastControl-Option-Command-Comma (,)
Increase contrastControl-Option-Command-Period (.)

1. MacBook Pro (15-inch, Late 2016), MacBook Pro (13-inch, Late 2016, Four Thunderbolt 3 Ports)

2. To use VoiceOver and VoiceOver Utility, you might need to turn on "Use all F1, F2, etc. keys as standard function keys" in Keyboard preferences. You might also need to make VoiceOver ignore the next key press before you can use some of the other Mac keyboard shortcuts.

3. To use the zoom shortcuts, you might need to turn on "Use keyboard shortcuts to zoom" in Accessibility preferences.

4. To enable this shortcut, choose Apple menu  > System Preferences, then click Keyboard. In the Shortcuts tab, select Accessibility on the left, then select ”Invert colours” on the right.

Use your keyboard like a mouse

You can use your keyboard like a mouse to navigate and interact with items onscreen. Use the Tab key and arrow keys to navigate, then press Space bar to select an item.

  1. Choose Apple menu  > System Preferences, then click Keyboard.
  2. Click Shortcuts.
  3. From the bottom of the preferences window, select ”Use keyboard navigation to move focus between controls”. In macOS Mojave or earlier, this setting appears as an ”All controls” button instead.
Switch between navigation of all controls on the screen, or only text boxes and listsControl-F7 or Fn-Control-F7
Move to the next controlTab
Move to the previous controlShift-Tab
Move to the next control when a text field is selectedControl-Tab
Move the focus to the previous grouping of controlsControl-Shift-Tab
Move to the adjacent item in a list, tab group or menu
Move sliders and adjusters (Up Arrow to increase values, Down Arrow to decrease values)
Arrow keys
Move to a control adjacent to the text fieldControl–Arrow keys
Choose the selected menu itemSpace bar
Click the default button or perform the default actionReturn or Enter
Click the Cancel button or close a menu without choosing an itemEsc
Move the focus to the previous panelControl-Shift-F6
Move to the status menu in the menu barControl-F8 or Fn-Control-F8
Activate the next open window in the front appCommand–Grave accent (`)
Activate the previous open window in the front appShift–Command–Grave accent (`)
Move the focus to the window drawerOption–Command–Grave accent (`)

To use these shortcuts, first press Control-F2 or Fn-Control-F2 to put the focus on the menu bar.

Move from menu to menuLeft Arrow, Right Arrow
Open a selected menuReturn
Move to menu items in the selected menuUp Arrow, Down Arrow
Jump to a menu item in the selected menuType the menu item's name
Choose the selected menu itemReturn

Use Mouse Keys to move the mouse pointer

When Mouse Keys is turned on, you can use the keyboard or numeric keypad keys to move the mouse pointer.

Move up8 or numeric keypad 8
Move downK or numeric keypad 2
Move leftU or numeric keypad 4
Move rightO or numeric keypad 6
Move diagonally down and to the leftJ or numeric keypad 1
Move diagonally down and to the rightL or numeric keypad 3
Move diagonally up and to the left7 or numeric keypad 7
Move diagonally up and to the right9 or numeric keypad 9
Press the mouse buttonI or numeric keypad 5
Hold the mouse buttonM or numeric keypad 0
Release the mouse button. (full stop)

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