Why can't I add a hyperlink to the text that I type within Gmail while composing ? I've tried via mobile app, Chrome and internet browser.

You may have gmail set to send plain text instead of html in which case links appear just as text instead of something you can click.

You can’t just paste in the link or it shows as plain text. So, while typing the message, when you get to the place where you want to insert the link, hit Ctrl+K & a dialog box will open where you can name the link & then add the link in the appropriate box, then click OK. You won’t see the actual link but what you named the link. I think that you can name the link with the actual link if that’s what you prefer.

There is also an icon at the bottom of the message area that you can click on to open the dialog box to fill in the appropriate info. I think the icon is the 3rd from the left. If you hover over each icon, it will tell you what the icon represents.

Gee – I cut and paste links all the time in gmail without doing all that. I think @Lightlyseared might have the right answer.