With Bitly, you can take a long link (aka destination URL) like this one:
And shorten it to a link like this one:
Or, with a paid plan, add your own custom domain and a custom back-half to get a really unique and branded link, like this one:
When you create a link with Bitly, clicks on it will be redirected from Bitly to the destination URL you started with.
To do this, we issue a "301 redirect," a technique for making a webpage available under many URLs. Because Bitly doesn’t re-use or modify shortened links, our redirects are permanent.