In order to install the AfterShip extension, access your Magento 2 admin dashboard and navigate to System -> Web Setup Wizard.
Select the Component Manager.
From you can view your already installed Magento 2 extensions. Click on Install to add a new extension.
Select the magento/module-aftership extension from the list and click on the Install button.
Click on the Start Readiness Check button to see if you have the necessary components required for the extension.
Once successful, click on the Next button to continue. If any components are marked red, a link will be provided to you to check how to fix them.
The next step will prompt you to create a Backup. You can create a backup by clicking on the Create Backup button or deselect the options and click the Next button if you do not want to create a backup.
The last step will prompt you to install the extension again. Click the Install button to continue.
You will receive a confirmation once completed.