Hi, and welcome to the Forum.
The signiture field is not a clickable link and really intended for putting your personal or business name, or a brief message.
You CAN, however, upload a fully clickable direct link to your website, which appears under your profile name to the right. The Icon to click appears as a globe, next to the envelope (send e mail) or the 'PM' - where users can send you a private message.
Let me know if we can help with anything else
Legal, financial & procedural information for your life in Spain