Steps to Import Multiple Products in a Quotation:

1. Go to: Sales > Quotations
2. Click on the “Import” button (usually found in the list view).
3. Download a sample file to understand the required fields (optional but helpful).
4. Prepare your CSV or Excel file with the following necessary columns:
   • Order/Quotation ID (use the same ID for multiple product lines to group them in one quotation)
   • Customer
   • Product
   • Quantity
   • Unit Price
   • UoM (optional)
   • Description (optional)
   • Order Date (optional)

5. Once your file is ready, upload it via the import feature.

6.Odoo will group all lines with the same ID as one quotation with multiple products.

Hi,

You can add multiple products to the same quotation using the Order Lines / Product field. For more details, please refer to the blog: https://www.cybrosys.com/blog/how-to-import-sale-orders-and-purchase-orders-in-odoo-17 

Hope it helps

See https://www.odoo.com/documentation/saas-18.3/applications/essentials/export_import_data.html#import-one2many-relationships

Import one2many relationships

If a company wants to import a sales order with several order lines, a specific row must be reserved in the CSV file for each order line. The first order line is imported on the same row as the information relative to order. Any additional lines need an additional row that does not have any information in the fields relative to the order.

There is also a demo file available showcasing the structure: https://www.odoo.com/documentation/saas-18.3/_downloads/a72f76fb9667dfb8c2795ec523e6f4b3/o2m_purchase_order_lines.csv