Pass information into POS transaction in new versions

I am currently using v6 of ERPNext where it is possible to pass into the POS module certain information from another app inside ERPNext. With the new version of POS that is now a “page” how can we do this?

To give an example:

We have a custom application inside ERPNext to perform our service business, when we finish there, we would like to then invoice the customer in a POS setting and therefore pass certain customer and application information into the POS page as to avoid double entry.

any help on this?

POS page is not extensible, maybe you will have to build the extension points and send a pull request.