mongodb is SCHEMALESS so it is so fast and it uses documents that are so close to human language thus is pretty easy to work with. the table below can be a good reference to seen in which environment which database is right for you.
to install mongodb on ubuntu you need to have a user with root privileges and configure firewall:
add a user : adduser mongo
add it to sudoers group :usermod -aG sudo mongo
allow SSH connection anf then enable whatever firewall you are using:
ufw allow OpenSSH ufw enable
now install the package:
sudo apt update sudo apt install mongodb-org
then start the service and then enable it so that it stars automatically after boot up:
sudo systemctl start mongod.service sudo systemctl enable mongod
to verify installation run:
mongo --eval 'db.runCommand({ connectionStatus: 1 })'