Hi ,

You can set a default value for the incoterms in sale order by using the set defaults.

First activate the developer mode, and select the required(value to save) incoterm in the in incoterms field, Then click laddy debugger button, the button near the logged in user name shown in the top right of the menu bar. On clicking the button, you can see the option set defaults, lick it then select the incoterm and save it

Thanks