Update Drupal module command.

ddev composer update "drupal/*" --with-all-dependencies
ddev drush updatedb
ddev drush cache:rebuild

Drush clear cache command,

ddev drush cr

This article will demonstrate how to install Drupal 9 in the DDEV environment.

Follow these steps

a. Open terminal

b. Create a folder in your DDEV web directory.

mkdir newweb

c. Change directory to the web folder.

cd newweb

d. Apply DDEV and create web folder.

ddev config --project-type=drupal9 --docroot=web --create-docroot

e. Start DDEV engine.