Need Advice on Automating Proposal Generation for Custom Design Services

Hello everyone,

I run a custom furniture business and recently started offering a "Custom Design Service," which includes a detailed set of CAD drawings and a comprehensive proposal for each client. I've set up a website using Squarespace and am looking for a way to streamline the generation and management of these proposals.

I'm manually creating proposals using the data collected through Squarespace forms, but I'm hoping to find a more automated solution. Does anyone have experience with automating proposal generation that integrates smoothly with Squarespace? Specifically, I'm looking for a tool or service that can:

1. Allow me to generate a detailed proposal document from form submissions.
2. Allow for easy customization and updates to the proposal template.
3. Integrate the proposal acceptance process and convert these into invoices upon project completion.

I would greatly appreciate any advice, recommendations on tools, or even workflows you've found effective. Integrations with Squarespace are preferred, but I'm open to external solutions that work with my current setup.

Thank you in advance for your help!