The column type determines the role of the column in the app.
You start defining your column when you give it a name in your spreadsheet and populate it with data of a particular type.
Controlling Column Order
AppSheet does its best to automatically order columns in order of importance. If you’re using the Tabular or Grouped List views, or the Table view, you can manually control column order.
After describing how AppSheet automatically orders columns, we describe how you can manually control column order.
You can decide which column is the key column.
Sometimes, the editor will give you an automatically computed key if there's no obvious unique identifier.
You can learn more about keys in What is a Key?.
You Can Decide Which Columns are Labels
Row Labels allow you to choose the most important columns in a table. One image column and one non-image column can be used as labels. All tables have a non-image label. The row labels are used to display references to rows in other tables.
A virtual column is a column of a table in the app that doesn't have an actual column in the underlying spreadsheet. Instead, it's automatically computed via an app formula expression.
Read more about virtual columns here.