Customizing the List view will allow you to see the information about your Leads, Accounts, and Deals just in the way you need it. You can hide those columns that you don't need, add those you do and rearrange them to make the most out of your data.
Any changes you make to the List configuration will only be visible under your own profile. It will not impact the rest of the team members of your organization.
Customize List View
To get started, go to either Leads, Accounts or Deals tab, depending on which list view you want to customize. Between the 'Save View' and 'Things You Can Do' buttons there is the 'List Configuration' button. Click it to display the available columns.
To remove a column from the view, just click on the checkbox next to its name. As you do this, you will notice that the column will disappear from the view. This doesn't mean that the information is no longer available, it was just hidden from the view.
To add a column, simply click on the checkbox square, right next to its name. The column will be added immediately and the view will adjust all the information.
You can also rearrange the columns in a way that best fits your needs. To do so, simply drag and drop the column to the desired spot.
Add Custom Fields
If you created Custom Fields, you can add them to your View. Custom Fields are usually located at the bottom of the 'List Configuration'.
To learn how to create Custom Fields, please visit the following tutorial: