Hi, Peter. Thank you for reaching out regarding the Proposal feature. Currently, this is in a Beta phase. This means that while the documentation is public, the feature is only available to small percentage of users at a time to ensure stability before a full global launch.
Since the Proposals tab is not yet visible in your Customer Hub, your account has not been included in this initial rollout phase. In the meantime, you can continue using the Estimate feature to process your quoting/proposal needs. All users will receive an email once the feature has been officially rolled out.
Please don't hesitate to leave us a response if you have other questions or concerns.