Lookup Icon

The Lookup icon (a magnifying glass) displays next to many fields.

There are several ways to make a selection.

Click in the field and start typing, and after you type a few characters then a drop-down list appears. Select an item from that list.
Click the icon and then a Select tab or pop-up opens. Click an entry in the grid to select it. Note that this method may save you time, as sometimes when you select from a grid, default values may be appear in more than one field after you make your selection and the pop-up closes.

Some Lookups allow for type-ahead capability, showing ID and description in the type-ahead pop-up. Some filter the list, so they only show you appropriate choices.