Connect PgAdmin4 on WSL2 Ubuntu 20.04.3 LTS

pgadmin.txt

sudo -u postgres psql -c 'SHOW config_file'

sudo nano /etc/postgresql/13/main/postgresql.conf      

# uncomment line 59: 

#------------------------------------------------------------------------------
# CONNECTIONS AND AUTHENTICATION
#------------------------------------------------------------------------------
# - Connection Settings -
listen_addresses = 'localhost'		# what IP address(es) to listen on;
#------------------------------------------------------------------------------
# Save file and restart

sudo service postgresql stop  

sudo service postgresql start

# https://www.pgadmin.org/download/pgadmin-4-windows/

# Download it here and install it.

# In the popup Create — Server window:

# General tab: I set Name to test

# Connection tab: I set Host name/address to 127.0.0.1 (Note: some post said you can set it as localhost, but it causes errors for me)
# port:5432
# Leave maintenance database and Username as default postgres
# Password: whatever password you set up earlier for PostgreSQL in WSL 2, click Save password

It is recommended to create a new superuser aside from postgres. The latter has a peer authentication type, which may cause an error when connecting by pgAdmin.

To create a user, run the following in the terminal.

$ su - postgres
$ createuser --interactive -P yourusername
Enter password for new role:
Enter it again:
Shall the new role be a superuser? (y/n) y

Test it by

$ psql -U yourusername -h 127.0.0.1 postgres

THANKS:))