Rename system fields

Hi There, is it possible to rename certain field on the preset templates. For example in the sales invoice, is it possible to rename Due date to Payable by?

Yes, you can do it by creating a custom theme and using a replace filter. There is an example of the technique in this Guide, although you will need to figure out which line of the code to modify:

If you can’t figure it out from there, you should probably get local coding support.