A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Text boxes on a userform don't act as hyperlinks.
You could add a command button with the following line in its On Click event procedure:
ActiveWorkbook.FollowHyperlink Me.TextBoxWebaddress
Alternatively, use a label, set its Caption property to the website address and use the above line in the On Click event procedure of the label.
If you make the caption blue and underlined, it will even look like a hyperlink.