You can change it with custom code in a module or overriding your theme.
You can also use the Better Exposed Filters module. Change the Exposed form options in your Views to use that module option. Then in the further settings you'll be able to override what the options are called for each filter separately.
Drupal 7 also had Views Advanced Labels.
Use this ...
To create a view from a database table instead of using hook_views_data you can use Views Custom Table module:
View custom table module provide you functionality to integrate your custom table data to views, and access all it's column in views. This module use hook_view_data to add custom tables in views.
it's easy just follow the 7 steps in How to use ...