If you use Postgres for some reason, you might be wondering how the heck you want to dump the SQL database using PgAdmin 4.
Well, sorry to say, there hasn't been luck for me, and probably for you too.
Now, go ahead and launch your windows power shell, and type this:
PS C:\Program Files\PostgreSQL\11\bin> ./pg_dump.exe -U postgres -t
You will find your SQL dump in the my_table.sql.
Have fun !