In order to access the CRM settings, Click on the "CRM Settings" link thats given in the top header section.

Click on crm settings - BangDB

Click on "More CRM Settings"

Click on setup crm - BangDB

Go to the "Lead Update Template" and select a group. ( These fields are defined at the group level )

Crm editing - BangDB

Once the group is selected. Click on Start Adding.

Crm editing - BangDB

Add the fields

Crm editing - BangDB

Once the changes are done. Click on Save.

The fields you add here, will appear inside each leads ( for the companies which are inside this group ) and users will be able to edit those fields for each lead.

Crm editing - BangDB