Overleaf is an online LaTeX editor. More details are at https://www.overleaf.com/edu/cambridge
If you don’t have an Overleaf account, you can create one by going to https://www.overleaf.com/edu/cambridge
If you have an existing account (free or paid) registered to your @cam email address, when you login to Overleaf you should get the option to link to the University account. If not, try going to https://www.overleaf.com/edu/cambridge
If you have an existing account (free or paid) registered to another address, login to your account and go to ‘Account settings’ and add your @cam address. You should then get the option to link to the University account.
Any problems with this, please contact the IT Team on it@econ.cam.ac.uk.