What to do so that the lessons learned remain in the organization and are documented and do not go only in the knowledge of people?

I agree with Mark and Liana, the best way to keep the lessons learned is to collect them progressively throughout the project in a centralized location, such as a sharepoint file or another dedicated software. At the end of the project it is too late, as we often release our project resources throughout the lifecycle as their requirements and contributions reduce. Also, it is good to go in at the end of the project and do a summary of lessons learned and project briefing summary sheet to use for future projects or even proposals. (Don't forget pictures also should be included if the project produced a tangible item.)

While my organization at the plant level does not have a dedicated PMO to aid in project data storage, we have set up dedicated project files on our computer server. Each project has its own folder/files to include all lessons learned that have been documented throughout each project.

We have also started to file the same lessons learned by category in a separate file to aid in easier access for future searches. Our goal in this ongoing development is to have a very usable resource that PM's can access and use in future projects.

As a side note, I also include any Lessons Learned in project status reports that have been documented for each reporting period. This is usually a summary of the L.L. and will reference the server file location for the complete version.

Many organizations want to capture the knowledge, but sadly don't. The best I have found, that is easy, and somewhat consistent is what Mark describes. A central file store or SharePoint that contains the project information for later referral.

before project closure learner lesson must be shared by team members. Leason must be save for future projects help or guide. Usually a PMO must organize the project information, but when it does not exist, a common poit for share, or central server, must be a great help.If you dont have one in your company, this could be a good moment to start with it

I agree with Mark and Liana, the best way to keep the lessons learned is to collect them progressively throughout the project in a centralized location, such as a sharepoint file or another dedicated software. At the end of the project it is too late, as we often release our project resources throughout the lifecycle as their requirements and contributions reduce. Also, it is good to go in at the end of the project and do a summary of lessons learned and project briefing summary sheet to use for future projects or even proposals. (Don't forget pictures also should be included if the project produced a tangible item.)