# Install the public key for the repository (if not done previously):
sudo curl https://www.pgadmin.org/static/packages_pgadmin_org.pub | sudo apt-key add

# Create the repository configuration file:
sudo sh -c 'echo "deb https://ftp.postgresql.org/pub/pgadmin/pgadmin4/apt/$(lsb_release -cs) pgadmin4 main" > /etc/apt/sources.list.d/pgadmin4.list && apt update'

# Install for desktop mode only:
sudo apt install pgadmin4-desktop

参考: 官网