Units in inventory Items

I seem to have successfully added a column for unit type in the inventory details i.e. Pcs, and Set.
Can anyone advise how I can add the column in the invoices and Quotes?

Unit name will automatically show on invoices and quotes when selling inventory items.

Thanks Lubos for your response. I do get a UNIT PRICE column in the quotes but not a UNIT TYPE. some items are sold in feet while others in kgs an so on. That unit description column is what I’m trying to insert. I was able to add it to the inventory item but I cant get it to display, I also need to create a custom report which gives a summary of sales by item. E.g total sales for plastic pipes 4", pipe ends 2" and so on.
Thanks for taking the time and I appreciate your help.

Where have you entered your unit types? As a custom field and ticked add as column?
Unit name should be entered in the unit name box when creating inventory items, then, they will be seen (on quotes and invoices) in the quantity box just after the quantity number, as long as the standard template is being used.