HR 1384, titled the Medicare for All Act of 2019, succeeds HR 676, which had been introduced to every session of Congress since 2003. HR 676 was more of a descriptive bill, without much detail in only around 30 pages. HR 1384 is an expanded and updated version introduced by Rep. Pramila Jayapal (D-WA) in February 2019. It had over 115 cosponsors and had four Committee hearings. The full text, list of cosponsors, and other details about the bill are available at congress.gov here.
This Senate bill, also titled the Medicare for All Act of 2019, was introduced in April 2019 with 16 cosponsors by Sen. Bernie Sanders, who had introduced a nearly identical bill in the 2017 session. His bill is very similar, but not identical, to HR 1384. Details about the bill are available at congress.gov here.
Principal features of the two bills may be compared here.