what does commission mean?

a legal agreement that confirms what is needed, by whom and by when

what does formal mean?

a detailed written brief

what does informal mean?

a verbal conversation or a simple outline document

what is a meeting/ discussion?

a verbal method to explain what is wanted using an informal process but may generate written minutes of what was agreed

what does negotiated mean?

a two way discussion with the aim of reaching agreed solution.

what does written mean?

a formal document that confirms what is wanted and by when stating all the relevant information

Further information and clarification can be sorted to remove ambiguities and gather more detail eg discussion, email,