Each Facebook post has a timestamp on the top, like Just now, 3 mins, or Yesterday. This timestamp contains the link to your post. To copy it, hover your mouse over the timestamp, right-click, and select Copy link address.
If you are using the Facebook app on a mobile device, follow the steps below:
In the Facebook app, navigate to the post that you want to get the link for.
Tap the Share button located underneath the post.
Under Share to options tap Copy link to copy the link to your clipboard.