You can enable the Edit Quote (New) button in Salesforce quote layouts using the Lightning Experience.

1. In your Salesforce org, click the Quotes tab.
2. Click and select Edit Object.
3. Click Page Layouts in the left navigation menu, and click Quote Layout - Default V8.0 layout. This layout determines the components exposed on the Quote Summary page.
   Note:

   • For Amend Quotes, click the Quote Layout - Amendment v8.0 layout.
   • For Renew Quotes, click the Quote Layout - Renewal V8.0 layout
4. From the box at the top in the main region, click Buttons in the left pane.
5. Drag and drop the Edit Quote (New) button to the Salesforce Mobile and Lightning Experience Actions section.
6. Click Save.