Client side

Using javascript you can create, update and delete a cookie

// creating a cookie
document.cookie = "username=jeff; expires=Thu, 01 Jan 2020 00:00:00 UTC; path=/;"

// deleting a cookie (setting expiration in the past)
document.cookie = "username=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=/;"

DEMO

Server side

Sending a Set-Cookie header in the response will create a cookie on the client side

Set-Cookie: <cookie-name>=<cookie-value> 
Set-Cookie: <cookie-name>=<cookie-value>; Expires=<date>
Set-Cookie: <cookie-name>=<cookie-value>; Max-Age=<non-zero-digit>
Set-Cookie: <cookie-name>=<cookie-value>; Domain=<domain-value>
Set-Cookie: <cookie-name>=<cookie-value>; Path=<path-value>

DEMO