To enter a Relevé 1 (RL-1) when you don’t live in Québec and are using TurboTax Online; 

go to the Income Tab > click directly on T-Slips > check the T4 slip box > a dropdown appears "I worked in Quebec and received a Relevé 1 slip" which must be checked. You can then proceed and "enter a new T4 slip" or "edit" an existing one. Box E will appear near the bottom of the slip page. 

https://turbotax.community.intuit.ca/replies/3231089