Add Product Description to Salesforce Quote Templates Using a Formula Field

To include the Product Description in a Salesforce Quote template, follow these two steps: first create a formula field on the Quote Line Item object, then modify the Quote template to include it.
I. Create a formula field:

• Classic: Setup | Customize | Quotes | Quote Line Items | Fields
• Lightning: Gear Icon | Setup | Object Manager | Quote Line Items | Fields & Relationships

1. Click New
2. Choose Formula and click Next
3. Enter a field label
4. Choose Text for the return type and click Next
5. Under "Formula (Text) =", enter: Product2.Description and click Next
6. Select the Profiles you would like to have access to the field
7. Click Next
8. Click Save

II. Modify the Quote template:

• Classic: Setup | Customize | Quotes | Templates
• Lightning: Gear Icon | Setup | Feature Settings | Quotes | Quote Templates

1. Click Edit on the template you want to modify
2. Hover over the Quote Line Items section and click the Wrench icon
3. From the Available Fields column, click the field and transfer it to Selected Fields by clicking the Add button
4. Click Ok
5. Click Save

Note: Per Salesforce documentation, it is not recommended to use Description fields in formulas due to formula field size limits.