User need to have administrators role to be able to customize it.
Considering an example where i need to customize view list of my sales
orders.
Go to search → module def → CRM (as sales order is part of crm,
you can find it in “DocType”) → Item list
In each row, you will find transaction and if you want to add/remove
columns from view list edit “Fields” column.
Do a browser refresh after doing changes.