Be aware that the “URL Hacks” that we had been using in Salesforce Classic are not guaranteed to work in Lightning Experience because of a change in the way the UI constructs and handles URLs.
If you would like to implement a similar solution that will work in Lightning Experience, I recommend using a either a Visualforce Page with a Custom Button on the Detail Page or Related List to perform this function, a Quick Action or a custom Lightning Component.
I will be replacing this page with an updated method for performing the function described below, so please consider the risks before implementing this solution.
In Salesforce, when you click on the standard ‘New’ button on a Related List to create a new record on the child object from the record currently in context in a Detail Page, after you click ‘Save’ and save the new record, it returns you to the Detail Page for the newly created record by default. For parent-child object relationships that have high levels of data entry on the child object, this creates a user experience issue as the user will have to click on the link to the parent record in order to return to the Detail Page to continue adding child records or perform additional functions on the parent record.