It probably depends on how your correspondent inserted the "link". Thunderbird does not try and work out what information might be a URL like some other products that are prone to phishing by converting non links into links because some computer thinks they are. This forum does something stupid in linkfying. This forum is prone to guessing if text it meant to be a link and does a really poor job of it.linkThunderbird looks for HTTP:// and HTTPS:// at the start of web site URLS. If it is missing then the thing is not "linkified". That is on sending. Thunderbird makes no attempt to guess what your sender intended with regards to link. If they did not insert a link it does not display it as such, nor does it offer an open link on the right click menu like Firefox does for "selected text".

Thank you Matt, the link started out, https://, and then the name of the company. Does this help?

Do you know the mail app used by the sender? Some mobile apps, and even the Windows mail app (the built-in Outlook, not the Office app), fail to correctly format links to be clickable for the recipient. Senders with these apps should embed links in text like this to avoid the problem.