If your organization has added the Aspendora app to Teams, you'll find it in the Teams app bar with three tabs: Home, New ticket and Tickets.
Each tab has an Open in browser button that opens the portal, already signed in with your work account. (Microsoft doesn't allow the sign-in page to run inside Teams, so the portal itself opens in your browser.)
Don't see it? Ask your administrator, or use portal.aspendora.com directly. It works the same.