Need to auto increment the ID number each time I add data from form

I am very new to this. I have created a database for keeping track of items sold to people at an auction. It has the date and an Id number as well as other needed things such as quantity and price and total price.

I need the ID number to auto increment so every entry is unique (it will never need to be started over).

View your table which has the ID number with EDIT
Select the ID row
Click on the AUTOVALUE and set it to YES
Save you table
Now each time you add a new item the ID will auto increment.