The highly-rated 18-year-old has impressed for the Reds since making her debut at the age of 16, appearing in all but one of Scott Rogers’ sides matches in the 2017 FA WSL Spring Series.
Charles was also nominated for the 2016 NWFA's Women's Rising Star prize, having scored two goals for England U17s in their third-place play-off with Norway to help the Lionesses qualify for the U17 Women's World Cup last year with a 2-1 victory.
On her new Liverpool deal, Charles said: “I am delighted to have agreed a new contract with the club. We showed earlier this year in the Spring Series that we can compete with the top teams and I am confident that we can challenge for trophies over the next few seasons.