my macbookpro 16 Go RAM always full

Out of curiosity I ran the etrecheck. It shows Minor issue—heavy RAM usage.

Well it is a non-issue.

Heavy RAM usage yes, that is why I have 16 GB of RAM installed. Unused RAM is wasted RAM.

Memory pressure is all in the green, no yellow, no red. No problem. The macOS is managing RAM just fine.

The new way is for Mac to use all available RAM. Unused RAM is wasted RAM.

Look at your Activity Monitor.app for memory pressure in the red—this will be more insightful.

Use Activity Monitor on your Mac - Apple Support

The take home lesson don't try to micro manage RAM usage.

Since 10.9.x OS X 10.9 Mavericks: The Ars Technica Review | Ars Technica

I suggest you use the program created by Etresoft, a frequent contributor. It will provide a snapshot of your system which we can analyze to possibly determine the cause of your problem. Please use copy and paste as screen shots can be hard to read. On the screen with Options, please open Options and check the bottom 2 boxes before running. Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste into a reply. This will show what is running on your computer. No personal information is shown.

Etrecheck – System Information

What are you using to read the RAM usage? Some of those third-party "memory management" programs are unreliable.

If your computer is slow it could be due to unneeded third-party software. That is a major cause of "slow Mac" reports in these forums. We can check for known troublemakers if you post a configuration snapshot. Fortunately there is a safe and secure way to do that.

A respected and long-serving member of these communities has created a simple utility that will take a "snapshot" of your configuration without revealing any sensitive information about you and your computer. It is Etrecheck, and is available here:

http://etrecheck.com/

Run it, scroll down the left-hand pane and select Report" and, when its report displays, click the "Share Report" icon and then "Copy Report" from the resulting dropdown. Paste the entire report into a response to your own thread here. It will often allow us to quickly identify or eliminate software as the problem.

Go to Applications -> Utilities -> Activity Monitor -> Memory (in activity monitor). There you can see what's using your memory.