Columns are SharePoint containers for metadata and they can be created directly inside a content type or a column group. There are several ways to create columns.
The simplest method to create a new column is the following:
1.Click on the column you need to create in the Palette area.
2.Click on where the content type needs to be located within the Diagram area. You will be prompted to enter a name (which cannot be identical to any other column inside this content type).
NOTE: The new column will also be created inside the Custom Column Group within this site.
An alternative method is to create a new column inside a column group and then use that column in the content type. The method to do this is similar to the previous method, except the new column should be dropped inside a column group rather than a content type. Once the column is created you can drag and drop it from the diagram or the navigator into the destination content type.
A final option is to drag an existing column from any other content type or column group into the new content type. If a column already exists, this is not only the preferred method but the recommended one. This will reduce the number of similar columns that need to be maintained.
After creating the column, navigate to the Properties Tab in the Properties and Information area to add or change individual properties. These will vary based on the column type.