There is no apparent method of adding an external hyperlink to text in Report Designer.
Workforce Analytics Report Designer, or Online Report Designer.
There is currently, and deliberately, no way to add external hyperlinks to Analytics reports. This decision was made in the interests of security, as it is impossible to fully control the quality and safety of the destinations of all hyperlinks.
KBA , LOD-SF-ANA , Analytics & Reporting (Ad Hoc, YouCalc, ORD) , How To