For getting Magento URL there are mostly two common methods

1: Through cmd, connect ssh and run

php bin/magento info:adminuri

2: Through Magento files, after installing Magento, one file is created called env.php.

Go to Magento root directory and follow the path

app/etc/env.php

Open env.php in a text editor and search for frontName.

You can get a result something like that

'backend' =>

array (

'frontName' => 'admin_test',

),

Now take your base URL, for example, https://www.testmagento.com/ and add your front name into it.

Now admin URL is https://www.testmagento.com/admin_test/

I hope you can easily get your Magento admin URL.