Control the pointer using Mouse Keys on Mac
With Mouse Keys on your Mac, you can move the mouse pointer and press the mouse button using the keyboard or a numeric keypad. To use Mouse Keys, choose Apple menu 
in the sidebar, click Pointer Control on the right, then turn on Mouse Keys. (You may need to scroll down.)
Open Pointer Control settings for me
The following illustration shows the keys to use on a keyboard (the keys on the left) and on a numeric keypad (the keys on the right) when Mouse Keys is on.
Note: When Mouse Keys is on, you can’t use the keyboard or a numeric keypad to enter text.
Move the mouse pointer:
With a numeric keypad: Use the 7, 8, 9, 4, 6, 1, 2, 3 keys on the keypad.
With the keyboard: Use the 7, 8, 9, U, O, J, K, L keys.
Click a mouse button:
With a numeric keypad: Press 5 on the keypad.
With the keyboard: Press I.
Press and hold the mouse button:
With a numeric keypad: Press 0 (zero) on the keypad.
With the keyboard: Press M.
Release the mouse button:
With a numeric keypad: Press “.” (full stop) on the keypad.
With the keyboard: Press “.” (full stop).
Tip: You can use Accessibility Shortcuts to quickly turn Mouse Keys on or off.
You can also use keyboard shortcuts, assistive switches or facial expressions to perform mouse actions, such as left, right or double clicks. Choose Apple menu in the sidebar, click Pointer Control on the right, then turn on “Alternate pointer actions”. (You may need to scroll down.) To customise the actions, click the Info button 
.