For Microsoft SQL Server Management Studio (SSMS) 19.1

• Connect to server
• Select database (not table)
• Right click on database
• Select Tasks -> Import Data... *
• Select Flat File Source

*Do not select Import Flat File... directly. This launches new verion of Import Wizard which does not allow import into already existing table.

I found a solution to import my data from a CSV file into an existing table using SQL Server Management Studio (SSMS). Here's a step-by-step guide on how to do it: Please note the main point or step that I was missing on earlier was not doing the right-click on the existing table in SQL Server Management Studio (SSMS) and choose "Import Data" from the context menu. This step is crucial because it initiates the data import process with the intention of importing data into the selected existing table, rather than creating a new one.

1. Open SQL Server Management Studio (SSMS): Start by launching SQL Server Management Studio on your computer.
2. Connect to Your Database: Connect to the SQL Server instance where your database and existing table are located. Enter the server name and your authentication credentials.
3. Locate the Existing Table: In the Object Explorer, navigate to the specific database that contains the table where you want to import data. Expand the "Tables" node to find your existing table.
4. Initiate the Import Data Wizard: Right-click on the name of the existing table. From the context menu that appears, select "Import Data..." This will open the SQL Server Import and Export Wizard.
5. Choose a Data Source: In the wizard, you'll see the "Choose a Data Source" page. Here, select "Flat File Source" as the data source. Click the "Browse" button to locate and select the CSV file you want to import.
6. Configure Data Source Settings: Depending on your CSV file's format, you may need to configure settings like the delimiter used in the file. Ensure these settings match your CSV file.
7. Specify Destination: Proceed to the "Choose a Destination" page. Choose "SQL Server Native Client" as the destination, and click the "Next" button to continue.
8. Choose Destination Table: On the "Specify Table Copy or Query" page, select the destination table where you want to import data. Make sure the "Enable identity insert" option is unchecked unless you specifically need to insert identity values from the CSV file. You can click the "Edit Mappings" button if you need to customize column mappings.
9. Review and Confirm: Review the settings on the subsequent pages of the wizard to ensure they match your requirements.
10. Save or Run the Package: On the "Save and Run Package" page, choose whether to save the SSIS package for future use or run it immediately. Make your selection, then click "Next" and "Finish."
11. Monitor the Import Process: The wizard will now begin importing data from the CSV file into your selected table. You can monitor the progress in the wizard interface.

Completion: Once the import is completed, you should see a summary of the process, including any potential errors or warnings that may have occurred during the import.