Secular Institutes are a form of consecrated life recognized on 2 February 1947 in the Church. These are associations of people who live ordinary life – engaged in all activities compatible with the Christian life whatever they are – and who strive to live these activities according to God so that the world may grow and develop as God has thought it. The words of Paul VI are precious in this regard, who lucidly grasped and made explicit the novelty of this form of Christian life.

“You are at a mysterious confluence between the two powerful currents of the Christian life, welcoming riches from both. You are lay people, consecrated as such by the sacraments of baptism and confirmation, but you have chosen to accentuate your consecration to God with the profession of the evangelical counsels, taken as obligations with a stable and recognized bond. Remain lay, committed to the secular values ​​proper and peculiar to the laity (Lumen Gentium, 31), but yours is a “consecrated secularity”.

Document Secular Institutes:  their Identity and their Mission

http://cmis-int.org/cmiswebsite/magisterio/magisterio_en/identity_mission_1984.pdf

Other documents and interventions of the popes can be found by opening this link:

https://www.cmis-int.org/en/    in the section   Basic Texts