A colleague has tried to share forms with me - and I've received a notification, but I can't see how to access their shared forms?

You'll need to register a Free account with JotForm using the same email address. The shared forms shall be displayed in your account by clicking on the username of the other account shown below Shared with you on the left side.

If you are not seeing the other account, please check the email address used. Also, please check wit the form owner to check the form access rights.

Hope this information helps.