Trump praised Sarah, saying she is a "very special person" and has "extraordinary talents". She is now planning to run for Governor of Arkansas.
"She is a very special person with extraordinary talents, who has done an incredible job! I hope she decides to run for Governor of Arkansas - she would be fantastic. Sarah, thank you for a job well done!," he added.
Sarah was considered as the most trusted aides of Trump.
Her resignation came as it has been the 94th consecutive day without a White House briefing, the longest stretch of time without a briefing, CNN reported.
Sanders succeeded Sean Spicer as press secretary at the White House in July 2017.