One amendment in particular was pushed into the spotlight. The amendment in question would alter term limits to be longer allowing Putin to continue being president. 65% of those eligible voted and 78% of those who voted supported changing the constitution. It was originally planned for April 22nd but then was rescheduled and altered due to the COVID-19 outbreak.
Source: https://www.dw.com/en/russias-putin-wins-referendum-on-constitutional-reforms/a-54018337