The last button in the top left corner of Record View is Select Fields. To manage the fields displayed in a record click on Select Fields to open a Displayable Fields dialog. In the Displayable Fields dialog select fields to display by clicking the checkbox to the left of a field name. To select or deselect multiple fields quickly and easily, use the Select All/Deselect All buttons in the top left corner of the dialog or click the checkbox next to the name of a group to select or deselect all fields within a group. Use the Reset button to the right of Select All/Deselect All buttons to remove your selections. Click Accept in the bottom right corner of the dialog to apply your field selections.
Please note that field selection options are applied to the record currently opened. Once the record is closed, and a new record is opened the previously selected displayable field choices will not be applied to the newly opened record.