Thank you for the screenshot.

wpForo allows you to customize and add the values of the fields under the gravatar.

You'll just need to copy the post.php file to your active theme's /wpforo/ folder (as described in the doc provided below) and add the new field anywhere you want.

The file located in the /wpforo/wpf-themes/classic/layouts/2 folder.

Also please note the value 2 is the Simplified Layout(#2), you can change this value depending on the layout you need to change.

To add the value of the custom field just use this function:

<?php echo implode( ', ', array_diff((array) wpforo_member($member, 'CUSTOM_FIELD_NAME'), array(0)) ) ?>

Just change the red marked code according to the custom field value.

Please follow this instruction to customize the wpForo files:

https://wpforo.com/docs/root/forum-themes/theme-customization/

Have attached the screenshot for your reference 

is it possible to show lets say city name or device name below the gravatar pic as shown in the screenshot :

Sorry, but you forgot to leave a screenshot. Please leave it here and we will check it.

is it possible to show lets say city name or device name below the gravatar pic as shown in the screenshot :

Like in the screenshot you can see Location below Gravatar can this be done ?

Do let me know .