The ASEAN Charter serves as a firm foundation in achieving the ASEAN Community by providing legal status and institutional framework for ASEAN. It also codifies ASEAN norms, rules and values; sets clear targets for ASEAN; and presents accountability and compliance.
The ASEAN Charter entered into force on 15 December 2008. A gathering of the ASEAN Foreign Ministers was held at the ASEAN Secretariat in Jakarta to mark this very historic occasion for ASEAN.
With the entry into force of the ASEAN Charter, ASEAN will henceforth operate under a new legal framework and establish a number of new organs to boost its community-building process.
In effect, the ASEAN Charter has become a legally binding agreement among the 10 ASEAN Member States.
Info is from ASEC website: https://asean.org/asean/about-asean/overview/