Appexchange App for automating documents in Salesforce

Appexchange App for automating documents in Salesforce With this app, the users should be able to generate documents from Salesforce with one click (documents like invoices, quotes, contracts, marketing materials, letters etc..) The idea is to have the app hosted on Salesforce platform and later add integrations to other systems - esign software, crms etc - I am open for suggestions on how to do that too How should it work: As a SF user, I create different templates (for invoices, quotes etc.) in e.g. Word using the merge fields. I need to be able to able to manage different templates on the app, decide what format is the final document in (e.g. Word or excel), adjust document name with merge fields, be able to generate “live” documents or documents for testing As a second step, I am able to map the merge fields from the document template with the fields in Salesforce and set different criteria when this mapping should be fired becuase I want the flexibility to have several mappings per document or fire the mapping only if the record in Salesforce meets certain criteria (e.g. if the record is only in the UK) Finally, with a button click on the salesforce record, the document is generated and delivery is automated (either stored to salesforce, sent to other systems (later) or sent via email etc...) Some other functions it should deliver: Merge documents - if record in SF meets certain criteria, merge the two PDFs together etc… ), delivery automation, generator reports (I can see what has been pushed from Salesforce to the document - this is important for testing the merges) Other info: Please provide scoping and timeline for the project Please share your budget suggestions and different options (maybe I have some requirements that would be super expensive in the specs above or not necessary, so please heads up on those) I am open to any suggestions on how this would be done the best and simplest way - I need to get a clear picture of how that app is working in the backend and must be able to maintain the app by myself afterwards (or be able to seek your help if needed) What I care is that my clients have the easiest possible job in generating documents - if you help me with that, we can talk about any future assignments