Championship clubs will have access to a £200m pool of interest-free loan funds, while a £50m grant will be made available for those in League One and Two.
Loans to second-tier clubs will be capped at £8.33m and would have to be repaid by June 2024.
EFL chairman Rick Parry welcomed the resolution after lengthy discussions.
"Our over-arching aim throughout this process has been to ensure that all EFL clubs survive the financial impact of the pandemic," he said.
"I am pleased that we have now reached a resolution on behalf of our clubs and as we have maintained throughout this will provide much-needed support and clarity following months of uncertainty."
Fans returned to some Football League grounds this week after England's national lockdown was replaced by a tier system.
However, with attendances limited by social-distancing measures, clubs are unlikely to profit from staging matches under such circumstances.
It is hoped that the deal agreed on Thursday will prevent the worst-case scenario of clubs going out of business.