How to share user permission across different servers and NFS folders?

I have a 3 different servers running Ubuntu 20. One of them is configured as the NFS host, and the other two as clients. The clients can mount the NFS shared folders and can write content on it sudo touch foo.txt. On the client servers, I have a wget process mirroring a website. I want my two clients servers to output the files from wget to /nfs/shared folder. On both servers, the process is executed like www-data user wget (...) -o /nfs/shared. None of the servers can write into the folder due to permission denied. Reading other questions here it seems like my users must have the same UUID to make sure the permission mask works properly. My question: - How can I maintain a list of users common across my n servers to make sure all of them can write into /nfs/shared?