Configure Postmark

Hi currently I’m using default email and now I wanted to use Postmark. for that, I place the API token on the email provider setting. but not receiving any emails, but from default mail, I have no issue.

do I need to change anything on the env file?
if yes please let me know what should be on MAIL_MAILER

current env

MAIL_MAILER="sendmail"

The best way to configure this is by using the GUI, in Settings > Email settings you can configure postmark directly from there