You can save your work and come back and finish later. Just click My Account (top right) then Save & Sign Out. (Click the first screenshot below for reference.) TurboTax will save your information and sign you out of your account.
When you are ready to resume, just sign in with the same user id and password you used before and click Take me to my return. Once the return opens, click Pick up where I left off. (Click the second and third screenshots below for reference.)
