QB Issue Resolution:
If what you wish to add is the field where a customer can write their signature on an Estimate form (if my assumption is right), then, you can add it by adding it as an additional footer.
Go to List menu and select Templates
Right click on your Estimate Template and choose Edit Template
At the bottom of the Basic Customization window, click on Additional Customization
Go to Footer tab and check Signature under the Print column
This will automatically add the Signature field on the actual form. Once the transaction is emailed, the customer will also see that it’s part of the form.
Additional information about the issue would also be helpful in providing other recommendations if possible.
Resolution for Issue 'How do you set up A signature for a Proposal or estimate that is being E-Mailed for QB 2015?' available: Yes (Solved).
Source: Intuit Community forum.
How do you set up A signature for a Proposal or estimate that is being E-Mailed for QB 2015?: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.Support for Customer
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