How can I make a redirect in WordPress?

Sometimes it’s good to be able to redirect people from one page to another page. As an example if you have a Forum, if you have a custom 404 page and so on...

CHAPTER 1: Add an instant redirect
CHAPTER 2: Add a redirect with time-delay
CHAPTER 3: If the codes don't work (depends on the theme)

CHAPTER 1: Add an instant redirect

1. To include an instant redirect Copy & paste the following code to the page you want the redirect to happen

2. Replace "url of the external site" with the url of the page or site you want people to be redirected to and that's it.

CHAPTER 2: Add a redirect with time-delay

1. To include a redirect with some time-delay Copy & paste the following code to the page you want the redirect to happen

Replace "url of the page" with the url of the page or site you want people to be redirected to
The number 4 in the code stands for the delay of time (in seconds) before people get redirected, you can change it to fit your case

CHAPTER 3: If the codes don't work (depends on the theme)

Depending on the theme you're using the codes I posted in Chapter 1 and Chapter 2 of this post don't work. In that case you could use a Plugin called Redirection.