Customizable Package Purchase Receipt Email

I'd like the Package Purchase Receipt Email to be customizable. I would like it to be a confirmation of the purchase with the receipt, but would also like to customize a welcome email detailing next steps to complete the questionnaire and I would like to be able to attach a budget calculator guide PDF and a guide to measuring/photographing the room PDF to this email so they have all the tools they will need upfront prior to completing the questionnaire