How to disable Quick Text in Salesforce Classic after enabling it?

Hi Kapil

In addition to the above response, you can find this by following the bellow steps:

1. Click on "Setup" button.
2. Search "Quick Text Settings" under Quick Text option in "Quick Search/Find" box.
3. Now you can disable it by unchecking the checkbox.
4. Then click on "Save" button.

Hope this helps you more.

Introduction Quick Text:

Quick text is predefined messages, like greetings, answers to common questions, and short notes. One can insert quick text in the case feed publisher, emails, chats, and more. Available in Salesforce Classic in Enterprise, Performance, Unlimited, and Developer Editions.

Quick Text Considerations -

General Considerations

• Editing the page layout for quick text changes the layout in both Salesforce Classic and Lightning Experience.
• Quick text works with leads. However, when you convert a lead, you must use quick text on the converted accounts, contacts, and opportunities.
• Administrators can customize the names of quick text channels, but we recommend that you don’t. Renaming standard values can prevent quick text messages from being available in the correct channels.
  

Salesforce Classic Considerations

• Subcategories are available only in Salesforce Classic.
• The Share button for individual quick text records is available only in Salesforce Classic.