To create custom Import/Export templates go to Settings>Documents

Select the Import/Export tab

Select New Template

You can then select from various options for import or export depending which area you require a custom export templates for (Inv,SO,PO etc..)

Import templates look like this 

You can create a name for the template and select the columns you would like to add to the template - you can add as many or as few columns as you require. Field position can 

Once you have filled in the relevant fields click save 

Export Templates look like this 

Name: Create a name for the export template

File Format: Select the file format the information will be exported to (Excel, CSV or CSV no headers)

Add Column: Select which columns you would like to export - you must click Add once you have selected a column to add it to the list of columns below.

Once you have chosen a name and a file format you can add columns to the custom template - select the column and click Add The field is then added to the list below - you can amend the header for each field

If you require a custom column that does not relate to any information in the system you can enter a column name in the Add column field

You can then select Add Custom Field...  to create a custom column

You must then select Add to add to the list of fields below

The custom column has now been added to the list

As this is a custom field you can set a Value for this field if required that would be filled in the value you would like to assign to this column when the list is exported.

If you add a field that can be displayed in multiple formats you can select the format you would like to export from the dropdown menu

Once you have added all the fields you require click Save

The new templates are now visible in the Document Templates list - I have added a custom import template for PO and a custom export template for Invoices

To now utilise these templates you can select them from within an invoice or PO

The custom import field is highlighted below in a PO

Once you select the Import Special Template you can import information in the custom import template you created.

The custom export field is available within an invoice - select the export button in the invoice

You can now select the custom export template from the dropdown menu and select Export to export in the format you selected earlier.