Before exporting, if you have sensitive information such as log-ins, api keys or anything else, you might consider setting those values to a variable and use the variable in your tasks so the value won't export with the task.
Make sure the task or profile is named - not a default name assigned by tasker.
If you have an anonymous task, either export the entire profile, or name the task. Once named, the task will be available in the tasks tab. To name an anonymous task, long press on it in the profile, a context menu will appear including an entry "name".
To name a profile if it isn't already, long press on the name to highlight the profile and, at the top, tap the square with the A. Any linked tasks will be exported with the profile they are linked to.
Now, long press on the name to highlight the task or profile. Go to the 3-dot menu and select export -> Description to Clipboard.
Now you'll be able to paste it. Be aware, it easier to use something like pastebin.com / hastebin.com and link to a post here. If you paste in a post here, the forum software will convert semicolons with characters directly after, into emoticons making it very hard to read.